Distribution of the Major Digestive Enzymes of Rana catesbeiana and the Effects of pH and Temperature on the Activities of Digestive Enzymes

The distribution of protease,lipase,amylase and cellulase in the digestive system of Rana catesbeiana and the effects of pH and temperature on the activities of these digestive enzymes were studied.The results indicated that the activities of digestive enzymes in different parts of digestive system were different significantly.The activities of protease from high to low were pancreas,stomach,the midgut,esophagus,the foregut and the hindgut,respectively.The optimum pH values of the protease in stomach,intestine and pancreas were 2.2,7.4 and 9.6,respectively,and their optimum temperature were 45 ℃,50 ℃ and 45 ℃,respectively.The activities of lipase from high to low were pancreas,the hindgut,the midgut,the foregut,the stomach and the esophagus,respectively.The optimum pH values of lipase in stomach,intestine and pancreas were 2.2,7.4 and 8.0,respectively,and their optimum temperature were equally 50 ℃.The activities of amylase from high to low were pancreas,the midgut,the hindgut,the foregut,the stomach and the esophagus,respectively.The optimum pH values of the amylase in stomach,intestine and pancreas were 7.0,8.0 and 9.6,respectively,and their optimum temperature were equally 35 ℃.No obvious cellulase activity was detected in the digestive system of Rana catesbeiana.