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MGP001958

UniProt Annotations

Entry Information
Gene Namemercaptopyruvate sulfurtransferase
Protein EntryTHTM_HUMAN
UniProt IDP25325
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=2; Name=1; IsoId=P25325-1; Sequence=Displayed; Name=2; IsoId=P25325-2; Sequence=VSP_055027;
Catalytic Activity3-mercaptopyruvate + cyanide = pyruvate + thiocyanate.
CautionWas originally thought to be rhodanese. {ECO:0000305|PubMed:1953758}.
DiseaseNote=Aberrant MPST activity is found in a few cases of mercaptolactate-cysteine disulfiduria (MCDU) characterized by the appearance of large quantaties of the sulfur-containing amino acid, beta-mercaptolactate-cysteine disulfide, in the urine (PubMed:4973015, PubMed:4690911 and PubMed:6945862). Some cases have associated mental retardation (PubMed:4973015 and PubMed:6945862).
DomainContains two rhodanese domains with different primary structures but with near identical secondary structure conformations suggesting a common evolutionary origin. Only the C- terminal rhodanese domain contains the catalytic cysteine residue (By similarity). {ECO:0000250}.
Enzyme RegulationBy oxidative stress, and thioredoxin. Under oxidative stress conditions, the catalytic cysteine site is converted to a sulfenate which inhibits the MPST enzyme activity. Reduced thioredoxin cleaves an intersubunit disulfide bond to turn on the redox switch and reactivate the enzyme.
FunctionTransfer of a sulfur ion to cyanide or to other thiol compounds. Also has weak rhodanese activity. Detoxifies cyanide and is required for thiosulfate biosynthesis. Acts as an antioxidant. In combination with cysteine aminotransferase (CAT), contributes to the catabolism of cysteine and is an important producer of hydrogen sulfide in the brain, retina and vascular endothelial cells. Hydrogen sulfide H(2)S is an important synaptic modulator, signaling molecule, smooth muscle contractor and neuroprotectant. Its production by the 3MST/CAT pathway is regulated by calcium ions (By similarity). {ECO:0000250}.
MiscellaneousThioredoxin (Trx) or dihydrolipoic acid (DHLA) are required to release hydrogen sulfide from the persulfide intermediate. {ECO:0000250}.
Sequence CautionSequence=AAH16737.1; Type=Erroneous initiation; Note=Translation N-terminally extended.; Evidence={ECO:0000305}; Sequence=CAG30409.1; Type=Erroneous initiation; Note=Translation N-terminally extended.; Evidence={ECO:0000305};
SimilarityContains 2 rhodanese domains. {ECO:0000255|PROSITE- ProRule:PRU00173}.
Subcellular LocationCytoplasm {ECO:0000250}. Mitochondrion {ECO:0000250}. Cell junction, synapse, synaptosome {ECO:0000250}.
SubunitMonomer; active form. Homodimer; disulfide-linked, inactive form. {ECO:0000250}.
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