Reaction Rates for the Chemiluminescence of Cypridina Luciferin Analogues with Superoxide: A Quenching Experiment with Superoxide Dismutase¹⁾

Abstract

Reaction rate constants for Superoxide (O₂^-) with Cypridina luciferin analogues (CLAs), 2-methyl-6-phenyl- and 2-methyl-6-(p-methoxyphenyl)-3, 7-dihydroimidazo[1, 2-a]pyrazin-3-ones (CLA and MCLA), and 2-methyl-6-[p-[2-[sodium 3-carboxylato-4-(6-hydroxy-3-xanthenon-9-yl)-phenylthioureylene]ethyleneoxy]phenyl]-3, 7-dihydroimidazo[1, 2-a]pyrazin-3-one(FCLA), were determined for the first time by using superoxide dismutase (SOD) for a quencher as 1.08 × 10⁸, 2.54 × 10⁸ and 8.5 × 10⁷ M^-1 sec^-1 in pH 7.1 buffer solutions at 25°C.