| Abstract: | Two phenoloxidase (PPO) isoforms were purified from Taiwanese black tiger shrimp (Penaeus monodon) purified via ammonium sulfate precipitation and high performance hydrophobic interaction chromatography on phenyl Sepharose CL-4B. Optimal DL-ã-3, 4-dihydroxyphenylalanine (D, L-DOPA) oxidation by these isoforms was observed to occur at pH 6.0, and at 45°C. The isoforms showed both mono- and di-PPO activities, and preferential medabolism of both monoand di-phenolic substrates lacking a carboxyl group either directly attached to the ring, or in the side chain moiety of the phenolic structure. |
