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MPST

Domain

Contains 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).

Function

Transfer 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.

Involvement in disease

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).

Cellular localization

  • Cytoplasm
  • Mitochondrion
  • Cell junction
  • Synapse
  • Synaptosome

Alternative names

  • 3-mercaptopyruvate sulfurtransferase
  • MST
  • TST2
  • MPST

Target type

Proteins

Molecular weight

33178Da