Effects of pH on amylase, cellulase and protease of the Angelwing clam, Pholas orientalis

This study aims to determine the effects of pH on the activity of the three digestive enzymes namely α-amylase, cellulase and protease in the crystalline style of the angelwing clam, Pholas orientalis. Laboratory assay of the three enzymes were also optimized to establish routine assay methods. α-Amylase activity increased from pH 3.0 and peaked at pH 6.0-8.0 beyond which it gradually decreased until pH 10.0. CM-cellulase activity abruptly increased from pH 3.0 reaching its peak at pH 6.0 beyond which an equally abrupt decline was observed until pH 9.0 and 10 where the activities were similar. Protease activity showed two maximal activities: a lower maximum at pH 6.0 and a higher one at pH 7.0; beyond pH 7.0, a decrease in enzyme activity was observed until pH 11.0. In conclusion, optimal pHs were determined for α-amylase, CM-cellulase and protease to be 6.0-80, 6.0 and 7.0, respectively