KINETIC-STUDIES OF THE INTERACTION BETWEEN SPERGUALIN OR 15-DEOXYSPERGUALIN AND AMINE OXIDASE FROM BOVINE PLASMA

Spergualin (SG) and 15-deoxyspergualin (DSG) are derivatives of spermi dine. Their substrate and inhibitor activities toward amine oxidase fr om bovine plasma were determined. SG was a good substrate of amine oxi dase next to spermidine. The Km and Spergualin (SG) and 15-deoxyspergu alin (DSG) are derivatives of spermidine. Their substrate and inhibito r activities toward amine oxidase from bovine plasma were determined. SG was a good substrate of amine oxidase next to spermidine. The Km an d V-max for SG were 465 mu M and 0.429 mu M/minute, respectively, wher eas the Km and V-max for spermidine were 111 mu M and 3.75 mu M/minute , respectively. Thus SG has about two-fold stronger affinity to amine oxidase than spermidine, but its catalysis rate was one ninth of sperm idine. In contrast, DSG was hardly oxidized and inhibited spermidine o xidation at low concentration. Affinity of both compounds for amine ox idase was determined by inhibition kinetics using benzylamine as subst rate. SG and DSG competitively inhibited amine oxidase activity showin g the Ki values of 175 mu M and 7.46 mu M, respectively.