ELECTROSTATIC CONTROL OF OXIDATIVE DEAMINATION CATALYZED BY BOVINE SERUM AMINE OXIDASE

The ionic-strength-dependence of steady-state kinetic parameters (k(c) and K-m') for non-biogenic (benzylamine, butylamine) and biogenic (spermine, spermidine) amines has been measured in the bovine serum amine oxidase reaction. The catalytic rate constant (k(c)) values are similar (0.9-2.5 s(-1)) for all the substrates studied and are almost constant over the experimental ionic strength range (24-155 mM). In contrast, K-m' values are in the range 6-2300 mu M and undergo a 4-12-fold increase with increasing ionic strength, parallelled by a decrease in catalytic efficiency. From an analysis of the k(c) and K-m' values and their dependence on ionic strength, we conclude that more than one negative site is involved in the binding of these amines and that the relative dielectric constant of the binding site is lower than that of aqueous solutions.