Tissue specific isozymes of octopine dehydrogenase in the cuttlefish,Sepia officinalis. The roles of octopine dehydrogenase and lactate dehydrogenase inSepia
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- Storey, K.B. J Comp Physiol B (1977) 115: 159. doi:10.1007/BF00692527
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The activities of octopine dehydrogenase (ODH) and lactate dehydrogenase (LDH) were assayed in the mantle, tentacles, skin, ventricle, branchial heart, ovary, nidamental gland, hepatopancreas, central brain, stellate ganglion, and gill of the cuttlefish,Sepia officinalis. The activities of ODH and LDH are not mutually exclusive; both dehydrogenases were present in each tissue.
LDH was present in heart-type (pyruvate inhibited) and muscle-type forms, the tissue distribution of these two forms being similar to that of the M4 and H4 LDH isozymes of vertebrate tissues.
Cellulose acetate and polyacrylamide gel electrophoresis revealed tissue specific forms of ODH. The enzymes from brain, mantle, and ventricle differ in electrophoretic mobility and several tissues (ex. gill, branchial heart) contain two separable forms of ODH activity.
ODH from hepatopancreas, mantle, brain, and ventricle were characterized kinetically, The brain and hepatopancreas enzymes were found to have the highest affinity for octopine and NAD+. Brain ODH exhibited the lowestKm for arginine and was potently product inhibited by octopine and NAD+.
The role of the ODH/octopine system inSepia appears to be analogous to, but not simply a substitute for, the LDH/lactate system of vertebrates. The possible biological significance of this “double dehydrogenase” system is dicussed.