Catalytic subunit of the molybdopterin synthase complex, a complex that catalyzes the conversion of precursor Z into molybdopterin. Acts by mediating the incorporation of 2 sulfur atoms from thiocarboxylated MOCS2A into precursor Z to generate a dithiolene group.
Subcellular locations: Cytoplasm, Cytosol
Highest levels are found in heart and skeletal muscle. Lower levels are present in brain, kidney and pancreas. Very low levels are found in lung and peripheral blood leukocytes.