Fumarylacetoacetate hydrolase: Difference between revisions

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== Structure ==
== Structure ==


The FAH [[gene]] is located on the chromosome 15q25.1 region and contains 14 [[exon]]s. It encodes a [[protein]] that is 46kDa in size. Multiple [[isoform]]s of the protein have been discovered that arose from [[alternative splicing]].
The FAH [[gene]] is located on the chromosome 15q25.1 region and contains 14 [[exon]]s. It encodes a [[protein]] that is 46kDa in size. Multiple [[isoform]]s of the protein have been discovered that arose from [[alternative splicing]]. The gene is mainly expressed in the liver and the kidney.


== Function ==
== Function ==
The fumarylacetoacetate hydrolase [[enzyme]] catalyzes the [[hydrolysis]] of [[4-fumarylacetoacetate]] into [[fumarate]] and [[acetoacetate]]. Other proteins that are involved in the subpathway include phenylalanine-4-hydroxylase ([[PAH]]), tyrosine aminotransferase ([[TAT]]), 4-hydroxyphenylpyruvate dioxygenase ([[HPD]]), homogentisate 1,2-dioxygenase ([[HGD]]), maleylacetoacetate isomerase ([[GSTZ1]]), fumarylacetoacetase (FAH)
The fumarylacetoacetate hydrolase [[enzyme]] catalyzes the [[hydrolysis]] of [[4-fumarylacetoacetate]] into [[fumarate]] and [[acetoacetate]]. This gene encodes the last enzyme in the subpathway that synthesizes [[acetoacetate]] and [[fumarate]] from L-[[phenylalanine]], which is part of a subpathway involved in [[phenylalanine]] degradation, part of the overall biochemical process of [[amino acid degradation]]. Other proteins that are involved in the phenylalanine degradation subpathway include phenylalanine-4-hydroxylase ([[PAH]]), tyrosine aminotransferase ([[TAT]]), 4-hydroxyphenylpyruvate dioxygenase ([[HPD]]), homogentisate 1,2-dioxygenase ([[HGD]]), maleylacetoacetate isomerase ([[GSTZ1]]), fumarylacetoacetase (FAH)


The protein has a number of conserved [[co-factor]] binding sites and probably requires [[Mg2+]] and [[Ca2+]] to funciton.
This gene encodes the last enzyme in the subpathway that synthesizes [[acetoacetate]] and [[fumarate]] from L-[[phenylalanine]].


==Clinical Significance==
==Clinical Significance==
[[Mutation]]s in the FAH gene cause [[type I tyrosinemia]] <ref>{{cite journal |vauthors=Phaneuf D, Lambert M, Laframboise R, Mitchell G, Lettre F, Tanguay RM |title=Type 1 hereditary tyrosinemia. Evidence for molecular heterogeneity and identification of a causal mutation in a French Canadian patient |journal=J. Clin. Invest. |volume=90 |issue=4 |pages=1185–92 |year=1992 |pmid=1401056 |pmc=443158 |doi=10.1172/JCI115979 |url=}} <ref>{{cite journal |vauthors=Labelle Y, Phaneuf D, Leclerc B, Tanguay RM |title=Characterization of the human fumarylacetoacetate hydrolase gene and identification of a missense mutation abolishing enzymatic activity |journal=Hum. Mol. Genet. |volume=2 |issue=7 |pages=941–6 |year=1993 |pmid=8364576 |doi= |url=}}</ref></ref>, an [[inborn error of metabolism]] that is characterized by increased [[tyrosine]] levels in the blood and urine of patients. <ref>http://www.omim.org/entry/276700</ref>
Mutations in the FAH gene cause [[type I tyrosinemia]].

Patients usually develop features including hepatic [[necrosis]] and [[renal tubular injury]] due to toxic accumulation of tyrosine and phenylalanine and may be treated by [[tyrosine]] and [[phenylalanine]] [[dietary restriction]] and [[liver transplantation]]. The disease is also known to cause [[hypertrophic cardiomyopathy]] in affected children. <ref>{{cite journal |vauthors=Mohamed S, Kambal MA, Al Jurayyan NA, Al-Nemri A, Babiker A, Hasanato R, Al-Jarallah AS |title=Tyrosinemia type 1: a rare and forgotten cause of reversible hypertrophic cardiomyopathy in infancy |journal=BMC Res Notes |volume=6 |issue= |pages=362 |year=2013 |pmid=24016420 |pmc=3846631 |doi=10.1186/1756-0500-6-362 |url=}}</ref>





Revision as of 20:02, 12 September 2015

Template:PBB Fumarylacetoacetase is an enzyme that in humans is encoded by the FAH gene located on chromosome 15. The FAH gene is thought to be involved in the catabolism of the amino acid phenylalanine in human. [1][2][3]

Structure

The FAH gene is located on the chromosome 15q25.1 region and contains 14 exons. It encodes a protein that is 46kDa in size. Multiple isoforms of the protein have been discovered that arose from alternative splicing. The gene is mainly expressed in the liver and the kidney.

Function

The fumarylacetoacetate hydrolase enzyme catalyzes the hydrolysis of 4-fumarylacetoacetate into fumarate and acetoacetate. This gene encodes the last enzyme in the subpathway that synthesizes acetoacetate and fumarate from L-phenylalanine, which is part of a subpathway involved in phenylalanine degradation, part of the overall biochemical process of amino acid degradation. Other proteins that are involved in the phenylalanine degradation subpathway include phenylalanine-4-hydroxylase (PAH), tyrosine aminotransferase (TAT), 4-hydroxyphenylpyruvate dioxygenase (HPD), homogentisate 1,2-dioxygenase (HGD), maleylacetoacetate isomerase (GSTZ1), fumarylacetoacetase (FAH)

The protein has a number of conserved co-factor binding sites and probably requires Mg2+ and Ca2+ to funciton.

Clinical Significance

Mutations in the FAH gene cause type I tyrosinemia Cite error: A <ref> tag is missing the closing </ref> (see the help page).</ref>, an inborn error of metabolism that is characterized by increased tyrosine levels in the blood and urine of patients. [4]

Patients usually develop features including hepatic necrosis and renal tubular injury due to toxic accumulation of tyrosine and phenylalanine and may be treated by tyrosine and phenylalanine dietary restriction and liver transplantation. The disease is also known to cause hypertrophic cardiomyopathy in affected children. [5]



References

  1. ^ Phaneuf D, Labelle Y, Bérubé D, Arden K, Cavenee W, Gagné R, Tanguay RM (Apr 1991). "Cloning and expression of the cDNA encoding human fumarylacetoacetate hydrolase, the enzyme deficient in hereditary tyrosinemia: assignment of the gene to chromosome 15". Am J Hum Genet. 48 (3): 525–35. PMC 1682993. PMID 1998338.
  2. ^ Agsteribbe E, van Faassen H, Hartog MV, Reversma T, Taanman JW, Pannekoek H, Evers RF, Welling GM, Berger R (Jun 1990). "Nucleotide sequence of cDNA encoding human fumarylacetoacetase". Nucleic Acids Res. 18 (7): 1887. doi:10.1093/nar/18.7.1887. PMC 330610. PMID 2336361.
  3. ^ "Entrez Gene: FAH fumarylacetoacetate hydrolase (fumarylacetoacetase)".
  4. ^ http://www.omim.org/entry/276700
  5. ^ Mohamed S, Kambal MA, Al Jurayyan NA, Al-Nemri A, Babiker A, Hasanato R, Al-Jarallah AS (2013). "Tyrosinemia type 1: a rare and forgotten cause of reversible hypertrophic cardiomyopathy in infancy". BMC Res Notes. 6: 362. doi:10.1186/1756-0500-6-362. PMC 3846631. PMID 24016420.{{cite journal}}: CS1 maint: unflagged free DOI (link)

Further reading

External links