Specific Substrates for Spectrophotometric Determination of Penicillin Acylase Activity

M. I. Youshko, T. A. Shamolina, D. F. Guranda, A. V. Synev, and V. K. Svedas^*

Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-3181; E-mail: vytas@enzyme.genebee.msu.su

^* To whom correspondence should be addressed.

Received January 30, 1988; Revision received February 9, 1998

---

Penicillin acylase substrates suitable for colorimetric determination of the enzyme activity have been tested in this study. The kinetic parameters (K_m and k_cat) have been elucidated for the following nine substrates: six phenylacetic acid derivatives (p-nitroanilide, p-nitrophenyl ester, p-nitro-m-carboxyanilide, p-nitro-o-carboxyanilide, p-nitro-o-hydroxyanilide, m-nitro-p-carboxyanilide), two D-phenylglycine derivatives (p-nitroanilide, p-nitro-m-carboxyanilide), and also p-nitrophenyl ester of acetic acid (p-nitrophenyl acetate). With the exception of p-nitrophenyl acetate, all the compounds studied are highly specific chromogenic substrates for penicillin acylase, but their reactivity is very variable and k_cat/K_m values are in a range from 0.8·10⁴ to 5·10⁶ M^-1·sec^-1.

---

KEY WORDS: penicillin acylase, method for determination of enzyme activity, chromogenic substrates

---