Glycerol-3-phosphate dehydrogenase

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Glycerol-3-phosphate dehydrogenase (NAD+)
Glycerol-3-phosphate dehydrogenase 1.png
Crystallographic structure of human glycerol-3-phosphate dehydrogenase 1.[1]
Identifiers
EC number 1.1.1.8
CAS number 9075-65-4
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Glycerol-3-phosphate dehydrogenase (quinone)
Identifiers
EC number 1.1.5.3
CAS number 9001-49-4
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
NAD-dependent glycerol-3-phosphate dehydrogenase N-terminus
PDB 1bg6 EBI.jpg
crystal structure of the n-(1-d-carboxylethyl)-l-norvaline dehydrogenase from arthrobacter sp. strain 1c
Identifiers
Symbol NAD_Gly3P_dh_N
Pfam PF01210
Pfam clan CL0063
InterPro IPR011128
PROSITE PDOC00740
SCOP 1m66
SUPERFAMILY 1m66
NAD-dependent glycerol-3-phosphate dehydrogenase C-terminus
PDB 1txg EBI.jpg
structure of glycerol-3-phosphate dehydrogenase from archaeoglobus fulgidus
Identifiers
Symbol NAD_Gly3P_dh_C
Pfam PF07479
Pfam clan CL0106
InterPro IPR006109
PROSITE PDOC00740
SCOP 1m66
SUPERFAMILY 1m66

Glycerol-3-phosphate dehydrogenase (GPDH) is an enzyme that catalyzes the reversible redox conversion of dihydroxyacetone phosphate (aka glycerone phosphate, outdated) to sn-glycerol 3-phosphate.[2]

Glycerol-3-phosphate dehydrogenase serves as a major link between carbohydrate metabolism and lipid metabolism. It is also a major contributor of electrons to the electron transport chain in the mitochondria.

Older terms for glycerol-3-phosphate dehydrogenase include alpha glycerol-3-phosphate dehydrogenase (alphaGPDH) and glycerolphosphate dehydrogenase (GPDH). However, glycerol-3-phosphate dehydrogenase is not the same as glyceraldehyde 3-phosphate dehydrogenase (GAPDH), whose substrate is an aldehyde not an alcohol.

Metabolic Function[edit]

GPDH plays a major role in lipid biosynthesis. Through the reduction of dihydroxyacetone phosphate into glycerol 3-phosphate, GPDH allows the prompt dephosphorylation of glycerol 3-phosphate into glycerol.[3] Additionally, GPDH is responsible for maintaining the redox potential across the inner mitochondrial membrane in glycolysis.[3]

Fig. 1. Schematic overview of fermentative and oxidative glucose metabolism of Saccharomyces cerevisiae. (A) upper part of glycolysis, which includes two sugar phosphorylation reactions. (B) fructose-1,6-bisphosphate aldolase, splitting the C6-molecule into two triose phosphates (C) triosephosphate isomerase, interconverting DHAP and GAP. (D) glycerol pathway reducing DHAP to glycerol-3-phosphate (G3P) by G3P dehydrogenase, followed by dephosphorylation to glycerol by G3Pase. (E) The lower part of glycolysis converts GAP to pyruvate while generating 1 NADH and 2 ATP via a series of 5 enzymes. (F) Alcoholic fermentation; decarboxylation of pyruvate by pyruvate decarboxylase, followed by reduction of acetaldehyde to ethanol. (G) mitochondrial pyruvate-dehydrogenase converts pyruvate to acetyl-CoA, which enters the tricarboxylic acid cycle. (H) external mitochondrial NADH dehydrogenases. (I) mitochondrial G3P dehydrogenase. Electrons of these three dehydrogenases enter the respiratory chain that the level of the quinol pool (Q). (J) internal mitochondrial NADH dehydrogenase. (K) ATP synthase. (L) generalized scheme of NADH shuttle. (M) formate oxidation by formate dehydrogenase.[4]

Reaction[edit]

The NAD+/NADH coenzyme couple act as an electron reservoir for metabolic redox reactions, carrying electrons from one reaction to another.[5] Most of these metabolism reactions occur in the mitochondria. To regenerate NAD+ for further use, NADH pools in the cytosol must be reoxidized. Since the mitochondrial inner membrane is impermeable to both NADH and NAD+, these cannot be freely exchanged between the cytosol and mitochondrial matrix.[4]

One way to shuttle this reducing equivalent across the membrane is through the Glycerol-3-phosphate shuttle, which employs the two forms of GPDH:

The reactions catalyzed by cytosolic (soluble) and mitochondrial GPDH are as follows:

Coupled reactions catalyzed by the cytosolic (GPDH-C) and mitochondrial (GPDH-M) forms of glycerol 3-phosphate dehydrogenase.[7] GPDH-C and GPDH-M use NADH and quinol (QH) as an electron donors respectively. GPDH-M in addition uses FAD as a co-factor.


Variants[edit]

There are two forms of GPDH:

Enzyme Protein Gene
EC number Name Donor / Acceptor Name Subcellular location Abbreviation Name Symbol
1.1.1.8 glycerol-3-phosphate dehydrogenase NADH / NAD+ Glycerol-3-phosphate dehydrogenase [NAD+] cytoplasmic GPDH-C glycerol-3-phosphate dehydrogenase 1 (soluble) GPD1
1.1.5.3 glycerol-3-phosphate dehydrogenase quinol / quinone Glycerol-3-phosphate dehydrogenase mitochondrial GPDH-M glycerol-3-phosphate dehydrogenase 2 (mitochondrial) GPD2

The following human genes encode proteins with GPDH enzymatic activity:

glycerol-3-phosphate dehydrogenase 1 (soluble)
Identifiers
Symbol GPD1
Entrez 2819
HUGO 4455
OMIM 138420
RefSeq NM_005276
UniProt P21695
Other data
EC number 1.1.1.8
Locus Chr. 12 q12-q13
glycerol-3-phosphate dehydrogenase 2 (mitochondrial)
Identifiers
Symbol GPD2
Entrez 2820
HUGO 4456
OMIM 138430
RefSeq NM_000408
UniProt P43304
Other data
EC number 1.1.5.3
Locus Chr. 2 q24.1

GPD1[edit]

Cytosolic Glycerol-3-phosphate dehydrogenase (GPD1), is an NAD+-dependent enzyme[8] that reduces dihydroxyacetone phosphate to glycerol-3-phosphate. Simultaneously, NADH is oxidized to NAD+ in the following reaction:

GPD1 Reaction Mechanism

As a result, NAD+ is regenerated for further metabolic activity.

GPD1 consists of two subunits,[9] and reacts with dihydroxyacetone phosphate and NAD+ though the following interaction:

Figure 4. The putative active site. The phosphate group of DHAP is half-encircled by the side-chain of Arg269, and interacts with Arg269 and Gly268 directly by hydrogen bonds (not shown). The conserved residues Lys204, Asn205, Asp260 and Thr264 form a stable hydrogen bonding network. The other hydrogen bonding network includes residues Lys120 and Asp260, as well as an ordered water molecule (with a B-factor of 16.4 Å2), which hydrogen bonds to Gly149 and Asn151 (not shown). In these two electrostatic networks, only the ε-NH3+ group of Lys204 is the nearest to the C2 atom of DHAP (3.4 Å).[1]

GPD2[edit]

Mitochondrial glycerol-3-phosphate dehydrogenase (GPD2), catalyzes the irreversible oxidation of glycerol-3-phosphate to dihydroxyacetone phosphate and concomitantly transfers two electrons from FAD to the electron transport chain. GPD2 consists of 4 identical subunits.[10]

X-ray structure of glycerol-3-phosphate dehydrogenase from Bacilius halodurans complexed with FAD. Northeast Structural Genomics Consortium target BhR167.[11]
GPD2 Reaction Mechanism

Response to Environmental Stresses[edit]

  • Studies indicate that GPDH is mostly unaffected by pH changes: neither GPD1 or GPD2 is favored under certain pH conditions.
  • At high salt concentrations (E.g. NaCl), GPD1 activity is enhanced over GPD2, since an increase in the salinity of the medium leads to an accumulation of glycerol in response.
  • Changes in temperature do not appear to favor neither GPD1 nor GPD2.[12]

Glycerol-3-phosphate shuttle[edit]

The cytosolic together with the mitochondrial glycerol-3-phosphate dehydrogenase work in concert. Oxidation of cytoplasmic NADH by the cytosolic form of the enzyme creates glycerol-3-phosphate from dihydroxyacetone phosphate. Once the glycerol-3-phosphate has moved through the inner mitochondrial membrane it can then be oxidised by a separate isoform of glycerol-3-phosphate dehydrogenase that uses quinone as an oxidant and FAD as a co-factor. As a result there is a net loss in energy, comparable to one molecule of ATP.[7]

The combined action of these enzymes maintains the NAD+/NADH ratio that allows for continuous operation of metabolism.

Role in Disease[edit]

The fundamental role of GDPH in maintaining the NAD+/NADH potential, as well as its role in lipid metabolism, makes GDPH a factor in lipid imbalance diseases, such as obesity.

Pharmacological target[edit]

The mitochondrial isoform of G3P dehydrogenase is though to be inhibited by metformin, a first line drug for type 2 diabetes. [15]

Structure[edit]

Glycerol-3-phosphate dehydrogenase consists of two protein domains. The N-terminal domain is an NAD-binding domain, and the C-terminus acts as a substrate-binding domain.[16]

See also[edit]

References[edit]

  1. ^ a b PDB 1X0V; Ou X, Ji C, Han X, Zhao X, Li X, Mao Y, Wong LL, Bartlam M, Rao Z (March 2006). "Crystal structures of human glycerol 3-phosphate dehydrogenase 1 (GPD1)". J. Mol. Biol. 357 (3): 858–69. doi:10.1016/j.jmb.2005.12.074. PMID 16460752. 
  2. ^ Ou X, Ji C, Han X, Zhao X, Li X, Mao Y, Wong LL, Bartlam M, Rao Z (31 March 2006). "Crystal Structures of Human Glycerol 3-phosphate Dehydrogenase 1 (GPD1)". Journal of Molecular Biology 357 (3): 858–869. doi:10.1016/j.jmb.2005.12.074. PMID 16460752. 
  3. ^ a b Harding JW, Pyeritz EA, Copeland ES, White HB (1975). "Role of glycerol 3-phosphate dehydrogenase in glyceride metabolism. Effect of diet on enzyme activities in chicken liver". Biochem. J. 146 (1): 223–9. PMC 1165291. PMID 167714. 
  4. ^ a b Geertman JM, van Maris AJ, van Dijken JP, Pronk JT (2006). "Physiological and genetic engineering of cytosolic redox metabolism in Saccharomyces cerevisiae for improved glycerol production". Metab. Eng. 8 (6): 532–42. doi:10.1016/j.ymben.2006.06.004. PMID 16891140. 
  5. ^ Ansell R, Granath K, Hohmann S, Thevelein JM, Adler L (14 January 1997). "The two isoenzymes for yeast NAD+-dependent glycerol 3-phosphate dehydrogenase encoded by GPD1 and GPD2 have distinct roles in osmoadaptation and redox regulation". The EMBO Journal 16 (9): 2179–2187. doi:10.1093/emboj/16.9.2179. PMC 1169820. PMID 9171333. 
  6. ^ Kota V, Rai P, Weitzel JM, Middendorff R, Bhande SS, Shivaji S (2 July 2010). "Role of glycerol-3-phosphate dehydrogenase 2 in mouse sperm capacitation". Molecular Reproduction and Development 77 (9): 773–783. doi:10.1002/mrd.21218. PMID 20602492. 
  7. ^ a b Stryer, Lubert; Berg, Jeremy Mark; Tymoczko, John L. (2002). "Chapter 18.5: Glycerol 3-Phosphate Shuttle". Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4684-0. 
  8. ^ Guindalini C, Lee KS, Andersen ML, Santos-Silva R, Bittencourt LR, Tufik S (2010). "The influence of obstructive sleep apnea on the expression of glycerol-3-phosphate dehydrogenase1 gene". Experimental Biology and Medicine 235 (1): 52–56. doi:10.1258/ebm.2009.009150. PMID 20404019. 
  9. ^ Bunoust O, Devin A, Avéret N, Camougrand N, Rigoulet M (4 February 2005). "Competition of Electrons to Enter the Respiratory Chain: A New Regulatory Mechanism of Oxidative Metabolism in Saccharomyces Cerevisiae". The Journal of Biological Chemistry 280 (5): 3407–3413. doi:10.1074/jbc.M407746200. PMID 15557339. 
  10. ^ Kota V, Dhople VM, Shivaji S (2009). "Tyrosine phosphoproteome of hamster spermatozoa: Role of glycerol-3-phosphate dehydrogenase 2 in sperm capacitation". Proteomics 9 (7): 1809–1826. doi:10.1002/pmic.200800519. PMID 19333995. 
  11. ^ Kuzin, A.P. "X-Ray structure of the glycerol-3-phosphate dehydrogenase from Bacillus halodurans complexed with FAD. Northeast Structural Genomics Consortium target BhR167.". www.pdb.org. Retrieved 16 May 2011. 
  12. ^ Kumar S, Kalyanasundaram GT, Gummadi SN (2011). "Differential response of the catalase, superoxide dismutase and glycerol-3-phosphate dehydrogenase to different environmental stresses in Debaryomyces nepalensis NCYC 3413". Curr. Microbiol. 62 (2): 382–7. doi:10.1007/s00284-010-9717-z. PMID 20644932. 
  13. ^ Xu SP, Mao XY, Ren FZ, Che HL (2011). "attenuating effect of casein glycomacropeptide on proliferation, differentiation, and lipid accumulation of in vitro Sprague-Dawley rat preadipocytes". Journal of Dairy Science 94 (2): 676–683. doi:10.3168/jds.2010-3827. PMID 21257036. 
  14. ^ Van Norstrand DW, Valdivia CR, Tester DJ, Ueda K, London B, Makielski JC, Ackerman MJ (14 May 2011). "Molecular and Functional Characterization of Novel Glycerol-3-Phosphate Dehydroogenase 1 like Gene (GPD1-L) Mutations in Sudden Infant Death Syndrome". Journal of the American Heart Association 116 (20): 2253–9. doi:10.1161/CIRCULATIONAHA.107.704627. PMC 3332545. PMID 17967976. 
  15. ^ Ferrannini E (2014). "The Target of Metformin in Type 2 Diabetes". New England Journal of Medicine 371 (16): 1547–1548. doi:10.1056/NEJMcibr1409796. ISSN 0028-4793. PMID 25317875. 
  16. ^ Suresh S, Turley S, Opperdoes FR, Michels PA, Hol WG (May 2000). "A potential target enzyme for trypanocidal drugs revealed by the crystal structure of NAD-dependent glycerol-3-phosphate dehydrogenase from Leishmania mexicana". Structure 8 (5): 541–52. doi:10.1016/s0969-2126(00)00135-0. PMID 10801498. 

Further reading[edit]

External links[edit]

This article incorporates text from the public domain Pfam and InterPro IPR011128

This article incorporates text from the public domain Pfam and InterPro IPR006109