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  • Title: New insights on the specificity of penicillin acylase.
    Author: Roa A, Castillón MP, Goble ML, Virden R, García JL.
    Journal: Biochem Biophys Res Commun; 1995 Jan 17; 206(2):629-36. PubMed ID: 7826381.
    Abstract:
    In contrast with the general thought that penicillin G acylases (PGAs) were only able to hydrolyse amides or esters of higly hydrophobic acids, we have demonstrated that the PGA from Kluyvera citrophila catalysed the hydrolysis of 4-nitrophenyl esters of acetic, propionic, butyric and valeric acids. Values of kcat. and kcat./Km were greatest for the first compound and less than values for benzylpenicillin by factors of 30 and 7, respectively. 4-Nitrophenyl acetate was hydrolysed faster than 2-nitrophenyl acetate but slower than phenyl acetate. The pH dependence of the reaction was similar to that of benzylpenicillin. Several experiments showed that hydrolysis of 4-nitrophenyl acetate was not catalysed by contaminating esterase activity. The implications for the structural basis of substrate binding are discussed. These substrates open, for the first time, a way to investigate the kinetic parameters of PGA at the presteady-state and provides a new perspective about the role of PGA in nature.
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