Cystathionine gamma-lyase

cystathionine gamma-lyase
Cysteine metabolism. Cystathionase catalyzes the lower reaction.
Identifiers
EC number	4.4.1.1
CAS number	9012-96-8
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
Search PMC articles PubMed articles

Cystathionine gamma-lyase (or cystathionase) is an enzyme which breaks down cystathionine into cysteine and α-ketobutyrate. Pyridoxal phosphate is a prosthetic group of this enzyme.

Cystathionine gamma-lyase also catalyses the following elimination reactions:

• L-homoserine to form H₂O, NH₃ and 2-oxobutanoate
• L-cystine, producing thiocysteine, pyruvate and NH₃
• L-cysteine producing pyruvate, NH₃ and H₂S

In some bacteria and mammals, including humans, this enzyme takes part in generating hydrogen sulfide.^[1]

Contents 1 Examples 2 Pathology 3 See also 4 External links 5 References

Examples

The following cystathionine gamma-lyase is expressed in humans:

cystathionase (cystathionine gamma-lyase) Identifiers Symbol CTH Entrez 1491 HUGO 2501 OMIM 607657 RefSeq NM_001902 UniProt P32929 Other data EC number 4.4.1.1 Locus Chr. 1 p31.1

Pathology

An deficiency is associated with cystathioninuria.

See also

• Cysteine metabolism

External links

• MeSH Cystathionine+gamma-lyase

References

Carbon-sulfur lyases (EC 4.4) 4.4.1 Cystathionine gamma-lyase - Cystathionine-beta-lyase - Leukotriene C4 synthase B enzm: 1.1/2/3/4/5/6/7/8/10/11/13/14/15-18, 2.1/2/3/4/5/6/7/8, 2.7.10, 2.7.11-12, 3.1/2/3/4/5/6/7, 3.1.3.48, 3.4.21/22/23/24, 4.1/2/3/4/5/6, 5.1/2/3/4/99, 6.1-3/4/5-6

Metabolism: amino acid metabolism · synthesis and catabolism enzymes (essential in CAPS) K→acetyl-CoA LYSINE→ Saccharopine dehydrogenase · Glutaryl-CoA dehydrogenase LEUCINE→ Branched chain aminotransferase · Branched-chain alpha-keto acid dehydrogenase complex · Isovaleryl coenzyme A dehydrogenase · Methylcrotonyl-CoA carboxylase · Methylglutaconyl-CoA hydratase · 3-hydroxy-3-methylglutaryl-CoA lyase TRYPTOPHAN→ Indoleamine 2,3-dioxygenase/Tryptophan 2,3-dioxygenase · Arylformamidase · Kynureninase · 3-hydroxyanthranilate oxidase · Aminocarboxymuconate-semialdehyde decarboxylase · Aminomuconate-semialdehyde dehydrogenase PHENYLALANINE→tyrosine→ (see below) G G→pyruvate →citrate glycine→serine→ Serine hydroxymethyltransferase · Serine dehydratase glycine→creatine: Guanidinoacetate N-methyltransferase · Creatine kinase alanine→ Alanine transaminase cysteine→ D-cysteine desulfhydrase threonine→ L-threonine dehydrogenase G→glutamate→ α-ketoglutarate HISTIDINE→ Histidine ammonia-lyase · Urocanate hydratase · Formiminotransferase cyclodeaminase proline→ Proline oxidase · Pyrroline-5-carboxylate reductase · 1-Pyrroline-5-carboxylate dehydrogenase/ALDH4A1 · PYCR1 arginine→ Ornithine aminotransferase · Ornithine decarboxylase · Agmatinase →alpha-ketoglutarate→TCA Glutamate dehydrogenase Other cysteine+glutamate→glutathione: Gamma-glutamylcysteine synthetase · Glutathione synthetase · Gamma-glutamyl transpeptidase glutamate→glutamine: Glutamine synthetase · Glutaminase G→propionyl-CoA→ succinyl-CoA VALINE→ Branched chain aminotransferase · Branched-chain alpha-keto acid dehydrogenase complex · Enoyl-CoA hydratase · 3-hydroxyisobutyryl-CoA hydrolase · 3-hydroxyisobutyrate dehydrogenase · Methylmalonate semialdehyde dehydrogenase ISOLEUCINE→ Branched chain aminotransferase · Branched-chain alpha-keto acid dehydrogenase complex · 3-hydroxy-2-methylbutyryl-CoA dehydrogenase METHIONINE→ generation of homocysteine: Methionine adenosyltransferase · Adenosylhomocysteinase regeneration of methionine: Methionine synthase/Homocysteine methyltransferase · Betaine-homocysteine methyltransferase conversion to cysteine: Cystathionine beta synthase · Cystathionine gamma-lyase THREONINE→ Threonine aldolase →succinyl-CoA→TCA Propionyl-CoA carboxylase · Methylmalonyl CoA epimerase · Methylmalonyl-CoA mutase G→fumarate PHENYLALANINE→tyrosine→ Phenylalanine hydroxylase · Tyrosine aminotransferase · 4-Hydroxyphenylpyruvate dioxygenase · Homogentisate 1,2-dioxygenase · Fumarylacetoacetate hydrolase tyrosine→melanin: Tyrosinase G→oxaloacetate asparagine→aspartate→ Asparaginase/Asparagine synthetase · Aspartate transaminase M: MET mt, k, c/g/r/p/y/i, f/h/s/l/o/e, a/u, n, m k, cgrp/y/i, f/h/s/l/o/e, au, n, m, epon m(A16/C10),i(k, c/g/r/p/y/i, f/h/s/o/e, a/u, n, m)