Quantitative enzymatic protection of d-amino acid methyl esters by exploiting ‘relaxed’ enantioselectivity of penicillin-G amidase in organic solvent

The lower enantioselectivity displayed by penicillin-G amidase (PGA) from E. coli in organic solvent has been exploited for developing a facile, fast and quantitative method for protection of esters of various d-amino acids via N-acylation. The feasibility of the deprotection of the acylated products was also demonstrated by employing PGA from two different sources in aqueous media. Experimental results are in agreement with previous calculations based on in silico models of the enzyme active site.