A NEW ULTRASENSITIVE BIOLUMINOGENIC ENZYME SUBSTRATE FOR BETA-GALACTOSIDASE

A derivative of D-luciferin, D-luciferin-O-beta-galactoside, was synthesized and used as highly sensitive substrate for beta-galactosidase. The substrate was physicochemically characterized. Enzymatic cleavage of the new compound by beta-galactosidase was demonstrated and kinetic constants K(m), V(max), k(cat) and k(cat)/K(m) K(m) have been determined. The compound has been proved to be a highly sensitive substrate for beta-galactosidase, permitting a limit of detection of 3.7 x 10(-19) mol of enzyme per assay.