Chemical synthesis and papain-catalysed hydrolysis of N-alpha-benzyloxycarbonyl-L-lysine p-nitroanilide.
The chemical synthesis of N-alpha-benzyloxycarbonyl-L-lysine p-nitroanilide (Z-Lys-pNA) is described in detail. The pH-dependence of the catalytic parameters kcat,' Km and kcat./Km for the papain-catalysed hydrolysis of Z-Lys-pNA are determined. kcat. and Km are pH-independent between pH 5 and pH 7.42, but the pH-dependence of kcat./Km is bell-shaped, decreasing at high and low pH values with pKa values of 7.97 and 4.40 respectively. The catalytic parameters and their pH-dependence are shown to be similar to those reported for other anilide substrates and it is concluded that the Km value of 0.01 mM previously reported [Angelides & Fink (1979) Biochemistry 18, 2355-2369] is incorrect. The possibility of accumulating a tetrahedral intermediate during the papain-catalysed hydrolysis of Z-Lys-pNA is discussed.
D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008239:Lysine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D010206:Papain / Q000378:metabolism*
C024992:N(alpha)-carbobenzoxylysine-4-nitroanilide; D010206:Papain; D008239:Lysine