| Eriocheir sinensis is the most commercial species in China. It naturally inhabits the north eastern China and Korea, and has been introduced to the southern provinces of China, North America and Western Europe. In the culture of crustacean, growth during larval development of brachyuran crabs has been studied as a function of diet, temperature, salinity, and other parameters. Some isozymes including acid phosphatase (ACP), alkaline phosphatase (AKP),esterase (EST), polyphenol oxidase (PPO), peroxidase superoxide dismutase (SOD) and lactate dehydrogenase (LDH) from four different tissues (liver, muscle, heart and gill) of Eriocheir sinensis in different developmental phases were analyzed with polyacrylamide gel electrophoresis, mensuration on the enzymes activity and enzyme cytochemical technique of electronic microscope. The results showed that pH optimum of ACP,AKP,SOD,POD,PPO is 4.5,9.5,8.0,6.5,6.0,respectively, and the temperature optimum is 50℃,40℃,40℃,45℃,45℃, respectively.The results also showed that the isozymes distributed widely in while LDH isozyme was detected no expression in liver and apparent tissue specificity was found between the enzyme band number and enzyme activity of the other isozymes. And the differences in isozyme patterns detected in four tissues during the developmental process are related with the function of the tissues. The complexity of isozyme changes in Eriocheir sinensis developmental stages is both a reflection of changes in cellular composition of specific tissues and changes in the rate and sequence of occurrence of the isozymes in different tissues. For example, during the three stages, the ACP isozyme patterns are similar in muscle and heart during development. However, in liver and gill the ACP isozyme patterns are significant differences, especially in liver. In liver, ACP-3 is only present in the immaturity crab which is lacking in ACP-1, meantime ACP-4 is observed in all three stages, but the isozyme activity becomes weaker obviously in the immature and mature crab, especially in the immature. So, in young crab ACP isozyme activity is the strongest in liver. In gill, the bands ACP-2,5 are present in all three stages, with ACP-2 isozyme activity reduces gradually.What's more, the ACP and AKP activities were mainly deposited in nucellar cell, endoplasmic reticulum and mitochondrium, they were showed in microvilli, around lipid droplet, mitochondrium and cellular endomembrane especially in liver. The SOD activity was sited in mitochondrium, cytoplasm in cells and around lipid droplet. And the POD and PPO activities were sited in specific organelle respectively: peroxisome and prophenoloxidase, but the POD granule did not detect in the muscle. The differences of the enzyme bands and activities in different developmental phases showed the changes of the metabolic mechanism for the calcium, lipid and carbohydrates during the development process of Eriocheir sinensis. And the differences in isozyme patterns detected in four tissues during the developmental process are related with the function of the tissues. The complexity of isozymes changes in Eriocheir sinensis developmental stages is both a reflection of changes in cellular composition of specific tissues and changes in the rate and sequence of occurrence of the isozymes in different tissues, so the changes of isozyme patterns can be an indicator for differentiation of tissues with the growth of Eriocheir sinensis.
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