Quantitative acylation of amino compounds catalysed by penicillin G acylase in organic solvent at controlled water activity

Covalently immobilised penicillin G acylase (PGA-450) accepts in toluene, a t controlled water activity (a(w)), a broad range of amino compounds as nuc leophiles in kinetically controlled acylation. Hydrolytic reactions were pr evented and complete conversions were achieved in short times even when wor king with an equimolar concentration of the substrates. The recovery of the products was facile, leading to high isolation yields. The obtained N-acyl ated derivatives Of L-amino acids can be used in further reactions, since n o purification steps are required in such conditions. This opens new perspe ctives to the application of PGA in selective protection of the amino funct ion for peptide synthesis. All attempts to perform esterification and trans esterification reactions with PGA in toluene, at the same a(w) as used for the acylation of amino compounds, were unsuccessful.