In biochemistry, transferase is the general name for the class of enzymes that enact the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of different biochemical pathways throughout biology, and are integral to some of life’s most important processes.
Transferases are involved in a myriad of reactions in the cell. Some examples of these reactions include the activity of CoA transferase, which transfers thiol esters, the action of N-acetyltransferase is part of the pathway that metabolizes tryptophan, and also includes the regulation of PDH, which converts pyruvate to Acetyl CoA. Transferases are also utilized during translation. In this case, an amino acid chain is the functional group transferred by a Peptidyl transferase. The transfer involves the removal of the growing amino acid chain from the tRNA molecule in the A-site of the ribosome and its subsequent addition to the amino acid attached to the tRNA in the P-site.
Mechanistically, an enzyme that catalyzed the following reaction would be a transferase:
- 1 History
- 2 Nomenclature
- 3 Classification
- 4 Reactions
- 4.1 EC 2.1: single carbon transferases
- 4.2 EC 2.2: aldehyde and ketone transferases
- 4.3 EC 2.3: acyl transferases
- 4.4 EC 2.4: glycosyl, hexosyl, and pentosyl transferases
- 4.5 EC 2.5: alkyl and aryl transferases
- 4.6 EC 2.6: nitrogenous transferases
- 4.7 EC 2.7: phosphorus transferases
- 4.8 EC 2.8: sulfur transferases
- 4.9 EC 2.9: selenium transferases
- 4.10 EC 2.10: metal transferases
- 5 Role in histo-blood group
- 6 Deficiencies
- 6.1 SCOT deficiency
- 6.2 CPT-II deficiency
- 6.3 Galactosemia
- 6.4 Choline acetyltransferase deficiencies
- 7 Uses in biotechnology
- 8 See also
- 9 References
Some of the most important discoveries relating to transferases occurred as early as the 1930s. Earliest discoveries of transferase activity occurred in other classifications of enzymes, including Beta-galactosidase, protease, and acid/base phosphatase. Prior to the realization that individual enzymes were capable of such a task, it was believed that two or more enzymes enacted functional group transfers.
Transamination, or the transfer of an amine (or NH2) group from an amino acid to a keto acid by an aminotransferase (also known as a "transaminase"), was first noted in 1930 by D. M. Needham, after observing the disappearance of glutamic acid added to pigeon breast muscle. This observance was later verified by the discovery of its reaction mechanism by Braunstein and Kritzmann in 1937. Their analysis showed that this reversible reaction could be applied to other tissues. This assertion was validated by Rudolf Schoenheimer's work with radioisotopes as tracers in 1937. This in turn would pave the way for the possibility that similar transfers were a primary means of producing most amino acids via amino transfer.
Another such example of early transferase research and later reclassification involved the discovery of uridyl transferase. In 1953, the enzyme UDP-glucose pyrophosphorylase was shown to be a transferase, when it was found that it could reversibly produce UTP and G1P from UDP-glucose and an organic pyrophosphate.
Another example of historical significance relating to transferase is the discovery of the mechanism of catecholamine breakdown by catechol-O-methyltransferase. This discovery was a large part of the reason for Julius Axelrod’s 1970 Nobel Prize in Physiology or Medicine (shared with Sir Bernard Katz and Ulf von Euler).
Classification of transferases continues to this day, with new ones being discovered frequently. An example of this is Pipe, a sulfotransferase involved in the dorsal-ventral patterning of Drosophilia. Initially, the exact mechanism of Pipe was unknown, due to a lack of information on its substrate. Research into Pipe's catalytic activity eliminated the likelihood of it being a heparan sulfate glycosaminoglycan. Further research has shown that Pipe targets the ovarian structures for sulfation. Pipe is currently classified as a Drosophilia heparan sulfate 2-O-sulfotransferase.
Systematic names of transferases are constructed in the form of "donor:acceptor grouptransferase." For example, methylamine:L-glutamate N-methyltransferase would be the standard naming convention for the transferase methylamine-glutamate N-methyltransferase, where methylamine is the donor, L-glutamate is the acceptor, and methyltransferase is the EC category grouping. This same action by the transferase can be illustrated as follows:
However, other accepted names are more frequently used for transferases, and are often formed as "acceptor grouptransferase" or "donor grouptransferase." For example, a DNA methyltransferase is a transferase that catalyzes the transfer of a methyl group to a DNA acceptor. In practice, many molecules are not referred to using this terminology due to more prevalent common names. For example, RNA Polymerase is the modern common name for what was formerly known as RNA nucleotidyltransferase, a kind of nucleotidyl transferase that transfers nucleotides to the 3’ end of a growing RNA strand. In the EC system of classification, the accepted name for RNA Polymerase is DNA-directed RNA polymerase.
Described primarily based on the type of biochemical group transferred, transferases can be divided into ten categories (based on the EC Number classification). These categories comprise over 450 different unique enzymes. In the EC numbering system, transferases have been given a classification of EC2. It is important to note, that hydrogen is not considered a functional group when it comes to transferase targets; instead, hydrogen transfer is included under oxidoreductases, due to electron transfer considerations.
|EC number||Examples||Group(s) transferred|
|EC 2.1||methyltransferase and formyltransferase||single-carbon groups|
|EC 2.2||transketolase and transaldolase||aldehyde or ketone groups|
|EC 2.3||acyltransferase||acyl groups or groups that become alkyl groups during transfer|
|EC 2.4||glycosyltransferase, hexosyltransferase, and pentosyltransferase||glycosyl groups, as well as hexoses and pentoses|
|EC 2.5||riboflavin synthase and chlorophyll synthase||alkyl or aryl groups, other than methyl groups|
|EC 2.6||transaminase, and oximinotransferase||nitrogenous groups|
|EC 2.7||phosphotransferase, polymerase, and kinase||phosphorus-containing groups; subclasses are based on the acceptor (e.g. alcohol, carboxyl, etc.)|
|EC 2.8||sulfurtransferase and sulfotransferase||sulfur-containing groups|
|EC 2.9||selenotransferase||selenium-containing groups|
|EC 2.10||molybdenumtransferase and tungstentransferase||molybdenum or tungsten|
EC 2.1: single carbon transferases
EC 2.1 includes enzymes that transfer single-carbon groups. This category consists of transfers of methyl, hydroxymethyl, formyl, carboxy, carbamoyl, and amido groups. Carbamoyltransferases, as an example, transfer a carbamoyl group from one molecule to another. Carbamoyl groups follow the formula NH2CO. In ATCase such a transfer is written as Carbamyl phosphate + L-aspertate L-carbamyl aspartate + phosphate.
EC 2.2: aldehyde and ketone transferases
Enzymes that transfer aldehyde or ketone groups and included in EC 2.2. This category consists of various transketolases and transaldolases. Transaldolase, the namesake of aldehyde transferases, is an important part of the pentose phosphate pathway. The reaction it catalyzes consists of a transfer of a dihydroxyacetone functional group to Glyceraldehyde 3-phosphate (also known as G3P). The reaction is as follows: sedoheptulose 7-phosphate + glyceraldehyde 3-phosphate erythrose 4-phosphate + fructose 6-phosphate.
EC 2.3: acyl transferases
Transfer of acyl groups or acyl groups that become alkyl groups during the process of being transferred are key aspects of EC 2.3. Further, this category also differentiates between amino-acyl and non-amino-acyl groups. Peptidyl transferase is a ribozyme that facilitates formation of peptide bonds during translation. As an aminoacyltransferase, it catalyzes the transfer of a peptide to an aminoacyl-tRNA, following this reaction: peptidyl-tRNAA + aminoacyl-tRNAB tRNAA + peptidyl aminoacyl-tRNAB.
EC 2.4: glycosyl, hexosyl, and pentosyl transferases
EC 2.4 includes enzymes that transfer glycosyl groups, as well as those that transfer hexose and pentose. Glycosyltransferase is a subcategory of EC 2.4 transferases that is involved in biosynthesis of disaccharides and polysaccharides through transfer of monosaccharides to other molecules. An example of a prominent glycosyltransferase is lactose synthase which is a dimer possessing two protein subunits. Its primary action is to produce lactose from glucose and UDP-glucose. This occurs via the following pathway: UDP-α-D-glucose + D-glucose UDP + lactose.
EC 2.5: alkyl and aryl transferases
EC 2.5 relates to enzymes that transfer alkyl or aryl groups, but does not include methyl groups. This is in contrast to functional groups that become alkyl groups when transferred, as those are included in EC 2.3. EC 2.5 currently only possesses one sub-class: Alkyl and aryl transferases. Cysteine synthase, for example, catalyzes the formation of acetic acids and cysteine from O3-acetyl-L-serine and hydrogen sulfide: O3-acetyl-L-serine + H2S L-cysteine + acetate.
EC 2.6: nitrogenous transferases
The grouping consistent with transfer of nitrogenous groups is EC 2.6. This includes enzymes like transaminase (also known as "aminotransferase"), and a very small number of oximinotransferases and other nitrogen group transferring enzymes. EC 2.6 previously included amidinotransferase but it has since been reclassified as a subcategory of EC 2.1 (single-carbon transferring enzymes). In the case of aspartate transaminase, which can act on tyrosine, phenylalanine, and tryptophan, it reversibly transfers an amino group from one molecule to the other.
The reaction, for example, follows the following order: L-aspartate +2-oxoglutarate oxaloacetate + L-glutamate.
EC 2.7: phosphorus transferases
While EC 2.7 includes enzymes that transfer phosphorus-containing groups, it also includes nuclotidyl transferases as well. Sub-category phosphotransferase is divided up in categories based on the type of group that accepts the transfer. Groups that are classified as phosphate acceptors include: alcohols, carboxy groups, nitrogenous groups, and phosphate groups. Further constituents of this subclass of transferases are various kinases. A prominent kinase is cyclin-dependent kinase (or CDK), which comprises a sub-family of protein kinases. As their name implies, CDKs are heavily dependent on specific cyclin molecules for activation. Once combined, the CDK-cyclin complex is capable of enacting its function within the cell cycle.
The reaction catalyzed by CDK is as follows: ATP + a target protein ADP + a phosphoprotein.
EC 2.8: sulfur transferases
Transfer of sulfur-containing groups is covered by EC 2.8 and is subdivided into the subcategories of sulfurtransferases, sulfotransferases, and CoA-transferases, as well as enzymes that transfer alkylthio groups. A specific group of sulfotransferases are those that use PAPS as a sulfate group donor. Within this group is alcohol sulfotransferase which has a broad targeting capacity. Due to this, alcohol sulfotransferase is also known by several other names including "hydroxysteroid sulfotransferase," "steroid sulfokinase," and "estrogen sulfotransferase." Decreases in its activity has been linked to human liver disease. This transferase acts via the following reaction: 3'-phosphoadenylyl sulfate + an alcohol adenosine 3',5'bisphosphate + an alkyl sulfate.
EC 2.9: selenium transferases
EC 2.9 includes enzymes that transfer selenium-containing groups. This category only contains two transferases, and thus is one of the smallest categories of transferase. Selenocysteine synthase, which was first added to the classification system in 1999, converts seryl-tRNA(Sec UCA) into selenocysteyl-tRNA(Sec UCA).
EC 2.10: metal transferases
The category of EC 2.10 includes enzymes that transfer molybdenum or tungsten-containing groups. However as of 2011, only one enzyme has been added: molybdopterin molybdotransferase. This enzyme is a component of MoCo biosynthesis in Escherichia coli. The reaction it catalyzes is as follows: adenylyl-molybdopterin + molybdate molybdenum cofactor + AMP.
Role in histo-blood group
The A and B transferases are the foundation of the human ABO blood group system. Both A and B transferases are glycosyltransferases, meaning they transfer a sugar molecule onto an H-antigen. This allows H-antigen to synthesize the glycoprotein and glycolipid conjugates that are known as the A/B antigens. The full name of A transferase is alpha 1-3-N-acetylgalactosaminyltransferase and its function in the cell is to add N-acetylgalactosamine to H-antigen, creating A-antigen. The full name of B transferase is alpha 1-3-galactosyltransferase, and its function in the cell is to add a galactose molecule to H-antigen, creating B-antigen.
It is possible for Homo sapiens to have any of four different blood types: Type A (express A antigens), Type B (express B antigens), Type AB (express both A and B antigens) and Type O (express neither A nor B antigens). The gene for A and B transferases is located on chromosome nine. The gene contains seven exons and six introns and the gene itself is over 18kb long. The alleles for A and B transferases are extremely similar. The resulting enzymes only differ in 4 amino acid residues. The differing residues are located at positions 176, 235, 266, and 268 in the enzymes.
Succinyl-CoA:3-ketoacid CoA transferase deficiency (or SCOT deficiency) leads to a buildup of ketones. Ketones are created upon the breakdown of fats in the body and are an important energy source. Inability to utilize ketones leads to intermittent ketoacidosis, which usually first manifests during infancy. Disease sufferers experience nausea, vomiting, inability to feed, and breathing difficulties. In extreme cases, ketoacidosis can lead to coma and death. The deficiency is caused by mutation in the gene OXTC1. Treatments mostly rely on controlling the diet of the patient.
Carnitine palmitoyltransferase II deficiency (also known as CPT-II deficiency) leads to an excess long chain fatty acids, as the body lacks the ability to transport fatty acids into the mitochondria to be processed as a fuel source. The disease is caused by a defect in the gene CPT2. This deficiency will present in patients in one of three ways: lethal neonatal, severe infantile hepatocardiomuscular, and myopathic form. The myopathic is the least severe form of the deficiency and can manifest at any point in the lifespan of the patient. The other two forms appear in infancy. Common symptoms of the lethal neonatal form and the severe infantile forms are liver failure, heart problems, seizures and death. The myopathic form is characterized by muscle pain and weakness following vigorous exercise. Treatment generally includes dietary modifications and carnitine supplements.
Galactosemia results from an inability to process galactose, a simple sugar. This deficiency occurs when the gene for galactose-1-phosphate uridylyltransferase (GALT) has any number of mutations, leading to a deficiency in the amount of GALT produced. There are two forms of Galactosemia: classic and Duarte. Duarte galactosemia is generally less severe than classic galactosemia and is caused by a deficiency of galactokinase. Galactosemia renders infants unable to process the sugars in breast milk, which leads to vomiting and anorexia within days of birth. Most symptoms of the disease are caused by a buildup of galactose-1-phosphate in the body. Common symptoms include liver failure, sepsis, failure to grow, and mental impairment, among others. Buildup of a second toxic substance, galactitol, occurs in the lenses of the eyes, causing cataracts. Currently, the only available treatment is early diagnosis followed by adherence to a diet devoid of lactose, and prescription of antibiotics for infections that may develop.
Choline acetyltransferase deficiencies
Choline acetyltransferase (also known as ChAT or CAT) is an important enzyme which produces the neurotransmitter acetylcholine. Acetylcholine is involved in many neuropsychic functions such as memory, attention, sleep and arousal. The enzyme is globular in shape and consists of a single amino acid chain. ChAT functions to transfer an acetyl group from acetyl co-enzyme A to choline in the synapses of nerve cells and exists in two forms: soluble and membrane bound. The ChAT gene is located on chromosome 10.
Decreased expression of ChAT is one of the hallmarks of Alzheimer’s disease. Patients with Alzheimer’s disease show a 30 to 90% reduction in activity in several regions of the brain, including the temporal lobe, the parietal lobe and the frontal lobe. However, ChAT deficiency is not believed to be the main cause of this disease.
Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease)
Patients with ALS show a marked decrease in ChAT activity in motor neurons in the spinal cord and brain. Low levels of ChAT activity are an early indication of the disease and are detectable long before motor neurons begin to die. This can even be detected before the patient is symptomatic.
Patients with Huntington’s also show a marked decrease in ChAT production. Though the specific cause of the reduced production is not clear, it is believed that the death of medium sized motor neurons with spiny dendrites leads to the lower levels of ChAT production.
Patients with Schizophrenia also exhibit decreased levels of ChAT, localized to the mesopontine tegment of the brain and the nucleus accumbens, which is believed to correlate with the decreased cognitive functioning experienced by these patients.
Sudden infant death syndrome (SIDS)
Recent studies have shown that SIDS infants show decreased levels of ChAT in both the hypothalamus and the striatum. SIDS infants also display fewer neurons capable of producing ChAT in the vagus system. These defects in the medulla could lead to an inability to control essential autonomic functions such as the cardiovascular and respiratory systems.
Congenital myasthenic syndrome (CMS)
CMS is a family of diseases that are characterized by defects in neuromuscular transmission which leads to recurrent bouts of apnea (inability to breathe) that can be fatal. ChAT deficiency is implicated in myasthenia syndromes where the transition problem occurs presynaptically. These syndromes are characterized by the patients’ inability to resynthesize acetylcholine.
Uses in biotechnology
Terminal transferases are transferases that can be used to label DNA or to produce plasmid vectors. It accomplishes both of these tasks by adding deoxynucleotides in the form of a template to the downstream end or 3' end of an existing DNA molecule. Terminal transferase is one of the few DNA polymerases that can function without an RNA primer.
The family of glutathione transferases (GST) is extremely diverse, and therefore can be used for a number of biotechnological purposes. Plants use glutathione transferases as a means to segregate toxic metals from the rest of the cell. These glutathione transferases can be used to create biosensors to detect contaminants such as herbicides and insecticides. Glutathione transferases are also used in transgenic plants to increase resistance to both biotic and abiotic stress. Glutathione transferases are currently being explored as targets for anti-cancer medications due to their role in drug resistance. Further, glutathione transferase genes have been investigated due to their ability to prevent oxidative damage and have shown improved resistance in transgenic cultigens.
Currently the only available commercial source of natural rubber is the Hevea plant (Hevea brasiliensis). Natural rubber is superior to synthetic rubber in a number of commercial uses. Efforts are being made to produce transgenic plants capable of synthesizing natural rubber, including tobacco and sunflower. These efforts are focused on sequencing the subunits of the rubber transferase enzyme complex in order to transfect these genes into other plants.
- "EC 2.7.7 Nucleotidyltransferases". Enzyme Nomenclature. Recommendations. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 14 November 2013.
- "Transferase". Genetics Home Reference. National Institute of Health. Retrieved 4 November 2013.
- Moore SA, Jencks WP (September 1982). "Model reactions for CoA transferase involving thiol transfer. Anhydride formation from thiol esters and carboxylic acids". J. Biol. Chem. 257 (18): 10882–92. PMID 6955307.
- Wishart, David. "Tryptophan Metabolism". Small Molecule Pathway Database. Department of Computing Science and Biological Sciences, University of Alberta. Retrieved 4 November 2013.
- Herbst, EA; Macpherson, RE; Leblanc, PJ; Roy, BD; Jeoung, NH; Harris, RA; Peters, SJ (Dec 4, 2013). "Pyruvate Dehydrogenase Kinase-4 Contributes to the Recirculation of Gluconeogenic Precursors During Post-Exercise Glycogen Recovery.". American journal of physiology. Regulatory, integrative and comparative physiology 306 (2): R102–7. doi:10.1152/ajpregu.00150.2013. PMID 24305065.
- Watson, James D. Molecular Biology of the Gene. Upper Saddle River, NJ: Pearson, 2013. Print.
- Boyce S, Tipton KF (2005). "Enzyme Classification and Nomenclature". eLS. doi:10.1038/npg.els.0003893.
- Morton RK (July 1953). "Transferase activity of hydrolytic enzymes". Nature 172 (4367): 65–8. doi:10.1038/172065a0. PMID 13072573.
- Cohen PP (September 1939). "Transamination in pigeon breast muscle". Biochem. J. 33 (9): 1478–87. PMC 1264599. PMID 16747057.
- Snell EE, Jenkins WT (December 1959). "The mechanism of the transamination reaction". Journal of Cellular and Comparative Physiology 54 (S1): 161–177. doi:10.1002/jcp.1030540413.
- Braunstein AE, Kritzmann MG (1937). "Formation and Breakdown of Amino-acids by Inter-molecular Transfer of the Amino Group". Nature 140 (3542): 503–504. doi:10.1038/140503b0.
- Schoenheimer, Rudolf (1949). The Dynamic State of Body Constituents. Hafner Publishing Co Ltd. ISBN 0028518004.
- Guggenheim KY (November 1991). "Rudolf Schoenheimer and the concept of the dynamic state of body constituents". J. Nutr. 121 (11): 1701–4. PMID 1941176.
- Hird , Rowsell (September 1950). "Additional transaminations by insoluble particle preparations of rat liver". Nature 166 (4221): 517–8. doi:10.1038/166517a0. PMID 14780123.
- Munch-Petersen A, Kalcar HM, Cutolo E, Smith EE (December 1953). "Uridyl transferases and the formation of uridine triphosphate; enzymic production of uridine triphosphate: uridine diphosphoglucose pyrophosphorolysis". Nature 172 (4388): 1036–7. doi:10.1038/1721036a0. PMID 13111246.
- "Physiology or Medicine 1970 - Press Release". Nobelprize.org. Nobel Media AB. Retrieved 5 November 2013.
- Lambalot, RH; Gehring, AM; Flugel, RS; Zuber, P; LaCelle, M; Marahiel, MA; Reid, R; Khosla, C; Walsh, CT (November 1996). "A new enzyme superfamily - the phosphopantetheinyl transferases.". Chemistry & biology 3 (11): 923–36. doi:10.1016/S1074-5521(96)90181-7. PMID 8939709.
- Wongtrakul, J; Pongjaroenkit, S; Leelapat, P; Nachaiwieng, W; Prapanthadara, LA; Ketterman, AJ (March 2010). "Expression and characterization of three new glutathione transferases, an epsilon (AcGSTE2-2), omega (AcGSTO1-1), and theta (AcGSTT1-1) from Anopheles cracens (Diptera: Culicidae), a major Thai malaria vector.". Journal of medical entomology 47 (2): 162–71. doi:10.1603/me09132. PMID 20380296.
- Sen, J; Goltz, JS; Stevens, L; Stein, D (Nov 13, 1998). "Spatially restricted expression of pipe in the Drosophila egg chamber defines embryonic dorsal-ventral polarity.". Cell 95 (4): 471–81. doi:10.1016/s0092-8674(00)81615-3. PMID 9827800.
- Moussian, B; Roth, S (Nov 8, 2005). "Dorsoventral axis formation in the Drosophila embryo--shaping and transducing a morphogen gradient.". Current biology : CB 15 (21): R887–99. doi:10.1016/j.cub.2005.10.026. PMID 16271864.
- Zhu, X; Sen, J; Stevens, L; Goltz, JS; Stein, D (September 2005). "Drosophila pipe protein activity in the ovary and the embryonic salivary gland does not require heparan sulfate glycosaminoglycans.". Development (Cambridge, England) 132 (17): 3813–22. doi:10.1242/dev.01962. PMID 16049108.
- Zhang, Z; Stevens, LM; Stein, D (Jul 28, 2009). "Sulfation of eggshell components by Pipe defines dorsal-ventral polarity in the Drosophila embryo.". Current biology : CB 19 (14): 1200–5. doi:10.1016/j.cub.2009.05.050. PMID 19540119.
- Xu, D; Song, D; Pedersen, LC; Liu, J (Mar 16, 2007). "Mutational study of heparan sulfate 2-O-sulfotransferase and chondroitin sulfate 2-O-sulfotransferase.". The Journal of Biological Chemistry 282 (11): 8356–67. doi:10.1074/jbc.M608062200. PMID 17227754.
- "EC 2 Introduction". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 5 November 2013.
- Shaw WV, Tsai L, Stadtman ER (February 1966). "The enzymatic synthesis of N-methylglutamic acid". J. Biol. Chem. 241 (4): 935–45. PMID 5905132.
- Lower, Stephen. "Naming Chemical Substances". Chem1 General Chemistry Virtual Textbook. Retrieved 13 November 2013.
- Hausmann, Rudolf. To grasp the essence of life : a history of molecular biology. Dordrecht: Springer. pp. 198–199. ISBN 978-90-481-6205-5.
- "EC 220.127.116.11". IUBMB Enzyme Nomenclature. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 12 November 2013.
- "EC2 Transferase Nomenclature". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 4 November 2013.
- "Transferase". Encyclopædia Britannica. Encyclopædia Britannica, Inc. Retrieved 4 November 2013.
- "EC 2.1.3: Carboxy- and Carbamoyltransferases". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 25 November 2013.
- "carbamoyltransferase". The Free Dictionary. Farlex, Inc. Retrieved 25 November 2013.
- "carbamoyl group (CHEBI:23004)". ChEBI: The database and ontology of Chemical Entities of Biological Interest. European Molecular Biology Laboratory. Retrieved 25 November 2013.
- Reichard P, Hanshoff G (1956). "Aspartate Carbamyl Transferase from Escherichia Coli". ACTA Chemica Scandinavica: 548–566.
- "ENZYME class 2.2.1". ExPASy: Bioinformatics Resource Portal. Swiss Institute of Bioinformatics. Retrieved 25 November 2013.
- "Pentose Phosphate Pathway". Molecular Biochemistry II Notes. The Biochemistry and Biophysics Program at Renssalaer Polytechnic Institute. Retrieved 25 November 2013.
- "EC 18.104.22.168 Transaldolase". Enzyme Structures Database. European Molecular Biology Laboratory. Retrieved 25 November 2013.
- Voorhees RM, Weixlbaumer A, Loakes D, Kelley AC, Ramakrishnan V (May 2009). "Insights into substrate stabilization from snapshots of the peptidyl transferase center of the intact 70S ribosome". Nat. Struct. Mol. Biol. 16 (5): 528–33. doi:10.1038/nsmb.1577. PMC 2679717. PMID 19363482.
- "ENZYME entry: EC 22.214.171.124". ExPASy: Bioinformatics Resource Portal. Swiss Institute of Bioinformatics. Retrieved 26 November 2013.
- "Keyword Glycosyltransferase". UniProt. UniProt Consortium. Retrieved 26 November 2013.
- Fitzgerald DK, Brodbeck U, Kiyosawa I, Mawal R, Colvin B, Ebner KE (April 1970). "Alpha-lactalbumin and the lactose synthetase reaction". J. Biol. Chem. 245 (8): 2103–8. PMID 5440844.
- "ENZYME entry: EC 126.96.36.199". ExPASy: Bioinformatics Resource Portal. Swiss Institute of Bioinformatics. Retrieved 26 November 2013.
- "EC 2.5". IntEnz. European Molecular Biology Laboratory. Retrieved 26 November 2013.
- Qabazard B, Ahmed S, Li L, Arlt VM, Moore PK, Stürzenbaum SR (2013). "C. elegans Aging Is Modulated by Hydrogen Sulfide and the sulfhydrylase/cysteine Synthase cysl-2". PLoS ONE 8 (11): e80135. doi:10.1371/journal.pone.0080135. PMC 3832670. PMID 24260346.
- "EC 2.6.2". IUBMB Enzyme Nomenclatur. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 28 November 2013.
- Kirsch JF, Eichele G, Ford GC, Vincent MG, Jansonius JN, Gehring H, Christen P (April 1984). "Mechanism of action of aspartate aminotransferase proposed on the basis of its spatial structure". J. Mol. Biol. 174 (3): 497–525. doi:10.1016/0022-2836(84)90333-4. PMID 6143829.
- "ENZYME entry:188.8.131.52". ExPASy: Bioinformatics Resource Portal. Swiss Institute of Bioinformatics. Retrieved 28 November 2013.
- "EC 2.7". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 4 December 2013.
- Yee A, Wu L, Liu L, Kobayashi R, Xiong Y, Hall FL (January 1996). "Biochemical characterization of the human cyclin-dependent protein kinase activating kinase. Identification of p35 as a novel regulatory subunit". J. Biol. Chem. 271 (1): 471–7. PMID 8550604.
- Lewis, Ricki (2008). Human genetics : concepts and applications (8th ed. ed.). Boston: McGraw-Hill/Higher Education. p. 32. ISBN 978-0-07-299539-8.
- "ENZYME Entry: EC 184.108.40.206". ExPASy: Bioinformatics Resource Portal. Swiss Institute of Bioinformatics. Retrieved 4 December 2013.
- "1aqy Summary". Protein Data Bank in Europe Bringing Structure to Biology. The European Bioinformatics Institute. Retrieved 11 December 2013.
- "EC 2.8 Transferring Sulfur-Containing Groups". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 11 December 2013.
- Negishi, M; Pedersen, LG; Petrotchenko, E; Shevtsov, S; Gorokhov, A; Kakuta, Y; Pedersen, LC (Jun 15, 2001). "Structure and function of sulfotransferases.". Archives of biochemistry and biophysics 390 (2): 149–57. doi:10.1006/abbi.2001.2368. PMID 11396917.
- "EC 2.8 Transferring Sulfur-Containing Groups". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 11 December 2013.
- "Enzyme 220.127.116.11". Kegg: DBGET. Kyoto University Bioinformatics Center. Retrieved 11 December 2013.
- Ou, Z; Shi, X; Gilroy, RK; Kirisci, L; Romkes, M; Lynch, C; Wang, H; Xu, M; Jiang, M; Ren, S; Gramignoli, R; Strom, SC; Huang, M; Xie, W (January 2013). "Regulation of the human hydroxysteroid sulfotransferase (SULT2A1) by RORα and RORγ and its potential relevance to human liver diseases.". Molecular endocrinology (Baltimore, Md.) 27 (1): 106–15. doi:10.1210/me.2012-1145. PMID 23211525.
- Sekura, RD; Marcus, CJ; Lyon, ES; Jakoby, WB (May 1979). "Assay of sulfotransferases.". Analytical Biochemistry 95 (1): 82–6. doi:10.1016/0003-2697(79)90188-x. PMID 495970.
- "EC 2.9.1". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 11 December 2013.
- Forchhammer, K; Böck, A (Apr 5, 1991). "Selenocysteine synthase from Escherichia coli. Analysis of the reaction sequence.". The Journal of Biological Chemistry 266 (10): 6324–8. PMID 2007585.
- "EC 2.10.1". School of Biological & Chemical Sciences at Queen Mary, University of London. Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB). Retrieved 11 December 2013.
- Nichols, JD; Xiang, S; Schindelin, H; Rajagopalan, KV (Jan 9, 2007). "Mutational analysis of Escherichia coli MoeA: two functional activities map to the active site cleft.". Biochemistry 46 (1): 78–86. doi:10.1021/bi061551q. PMID 17198377.
- Schomburg, Gerhard Michal, Dietmar (2010). Biochemical pathways : an atlas of biochemistry and molecular biology (2nd rev. ed. ed.). Oxford: Wiley-Blackwell. p. 140. ISBN 9780470146842.
- Nishida C, Tomita T, Nishiyama M, Suzuki R, Hara M, Itoh Y, Ogawa H, Okumura K, Nishiyama C (2011). "B-transferase with a Pro234Ser substitution acquires AB-transferase activity". Biosci. Biotechnol. Biochem. 75 (8): 1570–5. doi:10.1271/bbb.110276. PMID 21821934.
- "ABO ABO blood group (transferase A, alpha 1-3-N-acetylgalactosaminyltransferase; transferase B, alpha 1-3-galactosyltransferase) [ Homo sapiens (human) ]". NCBI. Retrieved 2 December 2013.
- Oxford dictionary of biochemistry and molecular biology (Rev. ed. ed.). Oxford [u.a.]: Oxford Univ. Press. 2000. p. 55. ISBN 0198506732.
- Oxford dictionary of biochemistry and molecular biology (Rev. ed. ed.). Oxford [u.a.]: Oxford Univ. Press. 2000. pp. 82–83. ISBN 0198506732.
- O'Neil, Dennis. "ABO Blood Groups". Human Blood: An Introduction to Its Components and Types. Behavioral Sciences Department, Palomar College. Retrieved 2 December 2013.
- "ABO Blood Group (Transferase A, Alpha 1-3-N-Acetylgalactosaminyltransferase;Transferase B, Alpha 1-3-Galactosyltransferase)". GeneCards: The Human Gene Compendium. Weizmann Institute of Science. Retrieved 2 December 2013.
- Moran, Lawrence. "Human ABO Gene". Retrieved 2 December 2013.
- Kidd, Kenneth. "ABO blood group (transferase A, alpha 1-3-N-acetylgalactosaminyltransferase; transferase B, alpha 1-3-galactosyltransferase)". Retrieved 2 December 2013.
- "Succinyl-CoA:3-ketoacid CoA transferase deficiency". Genetics Home Reference. National Institute of Health. Retrieved 4 November 2013.
- "SUCCINYL-CoA:3-OXOACID CoA TRANSFERASE DEFICIENCY". OMIM. Retrieved 22 November 2013.
- "SCOT deficiency". NIH. Retrieved 22 November 2013.
- "Succinyl-CoA 3-Oxoacid Transferase Deficiency". Climb National Information Centre. Retrieved 22 November 2013.
- "Carnitine plamitoyltransferase I deficiency". Genetics Home Reference. National Institute of Health. Retrieved 4 November 2013.
- Weiser, Thomas. "Carnitine Palmitoyltransferase II Deficiency". NIH. Retrieved 22 November 2013.
- "Galactosemia". Genetics Home Reference. National Institute of Health. Retrieved 4 November 2013.
- Dobrowolski SF, Banas RA, Suzow JG, Berkley M, Naylor EW (February 2003). "Analysis of common mutations in the galactose-1-phosphate uridyl transferase gene: new assays to increase the sensitivity and specificity of newborn screening for galactosemia". J Mol Diagn 5 (1): 42–7. doi:10.1016/S1525-1578(10)60450-3. PMC 1907369. PMID 12552079.
- Murphy, M; McHugh, B; Tighe, O; Mayne, P; O'Neill, C; Naughten, E; Croke, DT (July 1999). "Genetic basis of transferase-deficient galactosaemia in Ireland and the population history of the Irish Travellers.". European journal of human genetics : EJHG 7 (5): 549–54. doi:10.1038/sj.ejhg.5200327. PMID 10439960.
- Mahmood, U; Imran, M; Naik, SI; Cheema, HA; Saeed, A; Arshad, M; Mahmood, S (Nov 10, 2012). "Detection of common mutations in the GALT gene through ARMS.". Gene 509 (2): 291–4. doi:10.1016/j.gene.2012.08.010. PMID 22963887.
- "Galactosemia". NORD. Retrieved 22 November 2013.
- Elsas, LJ; Pagon, RA; Adam, MP; Bird, TD; Dolan, CR; Fong, CT; Stephens, K (1993). Galactosemia. PMID 20301691.
- Bosch, AM (August 2006). "Classical galactosaemia revisited.". Journal of Inherited Metabolic Disease 29 (4): 516–25. doi:10.1007/s10545-006-0382-0. PMID 16838075.
- Karadag, N; Zenciroglu, A; Eminoglu, FT; Dilli, D; Karagol, BS; Kundak, A; Dursun, A; Hakan, N; Okumus, N (2013). "Literature review and outcome of classic galactosemia diagnosed in the neonatal period.". Clinical laboratory 59 (9-10): 1139–46. doi:10.7754/clin.lab.2013.121235. PMID 24273939.
- Strauss, WL; Kemper, RR; Jayakar, P; Kong, CF; Hersh, LB; Hilt, DC; Rabin, M (February 1991). "Human choline acetyltransferase gene maps to region 10q11-q22.2 by in situ hybridization.". Genomics 9 (2): 396–8. doi:10.1016/0888-7543(91)90273-H. PMID 1840566.
- Braida, D; Ponzoni, L; Martucci, R; Sparatore, F; Gotti, C; Sala, M (Dec 6, 2013). "Role of neuronal nicotinic acetylcholine receptors (nAChRs) on learning and memory in zebrafish.". Psychopharmacology. doi:10.1007/s00213-013-3340-1. PMID 24311357.
- Stone, TW (September 1972). "Cholinergic mechanisms in the rat somatosensory cerebral cortex.". The Journal of physiology 225 (2): 485–99. PMC 1331117. PMID 5074408.
- Guzman, MS; De Jaeger, X; Drangova, M; Prado, MA; Gros, R; Prado, VF (March 2013). "Mice with selective elimination of striatal acetylcholine release are lean, show altered energy homeostasis and changed sleep/wake cycle.". Journal of Neurochemistry 124 (5): 658–69. doi:10.1111/jnc.12128. PMID 23240572.
- Oda Y (November 1999). "Choline acetyltransferase: the structure, distribution and pathologic changes in the central nervous system". Pathol. Int. 49 (11): 921–37. doi:10.1046/j.1440-1827.1999.00977.x. PMID 10594838.
- "Choline O-Acetyltransferase". GeneCards: The Human Gene Compendium. Weizmann Institute of Science. Retrieved 5 December 2013.
- Szigeti, C; Bencsik, N; Simonka, AJ; Legradi, A; Kasa, P; Gulya, K (May 2013). "Long-term effects of selective immunolesions of cholinergic neurons of the nucleus basalis magnocellularis on the ascending cholinergic pathways in the rat: a model for Alzheimer's disease.". Brain Research Bulletin 94: 9–16. doi:10.1016/j.brainresbull.2013.01.007. PMID 23357177.
- González-Castañeda RE, Sánchez-González VJ, Flores-Soto M, Vázquez-Camacho G, Macías-Islas MA, Ortiz GG (March 2013). "Neural restrictive silencer factor and choline acetyltransferase expression in cerebral tissue of Alzheimer's Disease patients: A pilot study". Genet. Mol. Biol. 36 (1): 28–36. doi:10.1590/S1415-47572013000100005. PMC 3615522. PMID 23569405.
- Rowland LP, Shneider NA (May 2001). "Amyotrophic lateral sclerosis". N. Engl. J. Med. 344 (22): 1688–700. doi:10.1056/NEJM200105313442207. PMID 11386269.
- Casas C, Herrando-Grabulosa M, Manzano R, Mancuso R, Osta R, Navarro X (March 2013). "Early presymptomatic cholinergic dysfunction in a murine model of amyotrophic lateral sclerosis". Brain Behav 3 (2): 145–58. doi:10.1002/brb3.104. PMC 3607155. PMID 23531559.
- Smith, R; Chung, H; Rundquist, S; Maat-Schieman, ML; Colgan, L; Englund, E; Liu, YJ; Roos, RA; Faull, RL; Brundin, P; Li, JY (Nov 1, 2006). "Cholinergic neuronal defect without cell loss in Huntington's disease.". Human Molecular Genetics 15 (21): 3119–31. doi:10.1093/hmg/ddl252. PMID 16987871.
- Karson, CN; Casanova, MF; Kleinman, JE; Griffin, WS (March 1993). "Choline acetyltransferase in schizophrenia.". The American Journal of Psychiatry 150 (3): 454–9. PMID 8434662.
- Mancama D, Mata I, Kerwin RW, Arranz MJ (October 2007). "Choline acetyltransferase variants and their influence in schizophrenia and olanzapine response". Am. J. Med. Genet. B Neuropsychiatr. Genet. 144B (7): 849–53. doi:10.1002/ajmg.b.30468. PMID 17503482.
- Mallard C, Tolcos M, Leditschke J, Campbell P, Rees S (March 1999). "Reduction in choline acetyltransferase immunoreactivity but not muscarinic-m2 receptor immunoreactivity in the brainstem of SIDS infants". J. Neuropathol. Exp. Neurol. 58 (3): 255–64. doi:10.1097/00005072-199903000-00005. PMID 10197817.
- Engel, AG; Shen, XM; Selcen, D; Sine, S (December 2012). "New horizons for congenital myasthenic syndromes.". Annals of the New York Academy of Sciences 1275: 54–62. doi:10.1111/j.1749-6632.2012.06803.x. PMC 3546605. PMID 23278578.
- Maselli RA, Chen D, Mo D, Bowe C, Fenton G, Wollmann RL (February 2003). "Choline acetyltransferase mutations in myasthenic syndrome due to deficient acetylcholine resynthesis". Muscle Nerve 27 (2): 180–7. doi:10.1002/mus.10300. PMID 12548525.
- Bowen, R. "Terminal Transferase". Biotechnology and Genetic Engineering. Colorado State University. Retrieved 10 November 2013.
- Kumar, Ashwani, Sudhir K. Sopory (2008). Recent advances in plant biotechnology and its applications : Prof. Dr. Karl-Hermann Neumann commemorative volume. New Delhi: I.K. International Pub. House. ISBN 9788189866099.
- Chronopoulou EG, Labrou NE (2009). "Glutathione transferases: emerging multidisciplinary tools in red and green biotechnology". Recent Pat Biotechnol 3 (3): 211–23. doi:10.2174/187220809789389135. PMID 19747150.
- Sytykiewicz H (2011). "Expression Patterns of Glutathione Transferase Gene (GstI) in Maize Seedlings Under Juglone-Induced Oxidative Stress". Int J Mol Sci 12 (11): 7982–95. doi:10.3390/ijms12117982. PMC 3233451. PMID 22174645.
- Shintani, David. "What is Rubber?". Elastomics. University of Nevada, Reno. Retrieved 23 November 2013.
- "DEVELOPMENT OF DOMESTIC NATURAL RUBBER-PRODUCING INDUSTRIAL CROPS THROUGH BIOTECHNOLOGY". USDA. Retrieved 23 November 2013.