EFFECT OF CARBON-DIOXIDE ON THE INACTIVATION OF FLORIDA SPINY LOBSTER POLYPHENOL OXIDASE

Florida spiny lobster (Panulirus argus) polyphenol oxidase (PPO) exposed to CO2 (1 atm) at 33, 38, and 43-degrees-C showed a decrease in enzyme activity with increased heating time. Enzyme inactivation by CO2 was faster for PPO heated at 43 than at 33 or 38-degrees-C. Inactivation kinetics revealed PPO was more labile to CO2 and heat in the range 33-43-degrees-C than to heat alone. Kinetic data also revealed that CO2, in addition to pH changes. was involved in the loss of PPO activity. Studies using gel electrophoresis showed no differences in protein patterns and isoelectric point between CO2-treated and non-treated control. The pH of CO2-treated PPO stock solution was brought back from 5.4 to 8.0 after 6 weeks of frozen-storage and no enzyme reactivation was observed.