3,3-dimethylcystein-S-yl group
3,3-dimethylcystein-s-yl group
A penicillin-derived group formed from benzylpenicillin via cleavage of the β-lactam and thiazolidine rings to afford a dimethyl-substituted cysteine entity able to link to the thiol group of a protein cysteine residue through a sulfur‒sulfur bond.