The Staphylococcus aureus transpeptidase Sortase A (SrtA) anchors virulence and colonization-associated surface proteins to the cell wall. SrtA selectively recognizes a C-terminal LPXTG motif. SrtA readily reacts with its native substrate Abz-LPETG-Dap(DNP)-NH2, cleaving it and catalyzing the formation of an amide bond between the carboxyl group of threonine and the amino group of cell-wall crossbridges.

L-3-Phenyllactic acid (or PLA) is a chiral aromatic compound involved in phenylalanine metabolism. It is likely produced from phenylpyruvate via the action of lactate dehydrogenase.

p60c-src substrate II is an efficient pentapeptide substrate for the tyrosine kinase pp60c-src.