Probably catalyzes the deacetylation of N-acetylcysteine (NAC) to acetate and cysteine. Is involved in a S-(2-succino)cysteine (2SC) degradation pathway that allows B.subtilis to grow on 2SC as a sole sulfur source, via its metabolization to cysteine. Binds 2 divalent metal cations per subunit. Amino-acid biosynthesis; L-cysteine biosynthesis. Cells lacking this gene do not lose the ability to grow on 2SC as the sulfur source because of the presence of other deacetylases that can compensate for scmP (yxeP) deficiency. In a triple mutant lacking this gene, ytnL and yhaA, the levels of NAC highly increases after addition of 2SC. Belongs to the peptidase M20 family.