Putative cysteine synthase that catalyzes the conversion of O-acetyl-L-serine (OAS) into cysteine, the last step in the cysteine biosynthesis pathway. However, this CS-like protein is unlikely to function in cysteine biosynthesis. It seems that in S.cerevisiae cysteine biosynthesis occurs exclusively through the cystathionine pathway and not via direct incorporation of sulfur into OAS. hydrogen sulfide + O-acetyl-L-serine = acetate + L-cysteine Selective removal from mitochondrial outer membrane is achieved by sorting into a mitochondrial-derived compartment, or MDC, followed by release through mitochondrial fission and elimination by autophagy. Present with 4650 molecules/cell in log phase SD medium. Belongs to the cysteine synthase/cystathionine beta-synthase family.