The beginnings of enzyme suicide

TheE. Coli enzyme -hydroxydecanoyl thioester dehydrase catalyzes the conversion of 3-hydroxydecanoyl-thioester to the corresponding 2,3 enoate and also the reversible isomerization of 2,3- and 3,4 enoates, 3-decynoyl thioesters inhibit all these reactions irreversibly. The mechanism responsible for these inhibitions involves enzyme-catalyzed conversion of 3-decynoyl thioester to 2,4 decadienoyl thioester followed by covalent interaction of the allene with an active site histidine. Enzyme inactivation results from the ability of the enzyme to convert a substrate analogue into a potent active site modifying reagent. A brief review is given of research on unsaturated fatty acid synthesis which inadvertently revealed the phenomenon of Enzyme Suicide.