Mitochondrial contribution to metabolic changes in the digestive gland of Mytilus galloprovincialis during anaerobiosis.

The activities of several enzymes and the levels of metabolites have been measured in the digestive gland of Mytilus galloprovincialis exposed to increasing hypoxia from 7 to 168 hr. A sharp decrease of pyruvate kinase was observed after 7 hr. The anoxic enzyme showed increased Km for phosphoenolpyruvate and decreased apparent Ki for alanine. Glyoxalase I was constant after up to 72 hr of exposure and then decreased. Phosphoenolpyruvate carboxykinase and alanopine dehydrogenase decreased. The metabolites alanine and succinate increased with hypoxia time, whereas D- and L-lactic and aspartic acids were undetectable and constant respectively. Mitochondrial formation of pyruvate from D-lactate was demonstrated in intact mitochondria isolated from the digestive gland of Mytilus galloprovincialis. The significance of the observed enzyme and metabolite changes in hypoxia is discussed in comparison with other invertebrate organisms. The role of mitochondria in the overall adaptive strategy of Mytilus galloprovincialis is discussed. J. Exp. Zool. 286:107-113, 2000. Copyright 2000 Wiley-Liss, Inc.