Studies on the anaerobic energy metabolism in the foot muscle of marine gastropod Patella caerulea (L.)

Abstract

1. 1. The foot muscle of P. caerulea has a complete sequence of glycolytic enzymes. The low activitiy of hexokinase, in comparison with the activities of glycogen phosphorylase and phosphofructokinase, indicate that glycogen is the main fuel oxidized. 2. 2. The reduction of aspartate content in combination with the accumulation of alanine and the presence of considerable activities of glutamate-oxaloacetate transaminase and glutamate-pyruvate transaminase indicates a coupled metabolism of glycogen and aspartate during exposure to air. 3. 3. From the changes in the concentration of the metabolites during exposure to air it appears that up to the second hour of anaerobiosis alanine, lactate and glutamate are the end-products which accumulate in the foot muscle of P. caerulea, whereas from the second to the fourth hour only succinte and alanine accumulate. 4. 4. The low activities of the Krebs cycle enzymes as well as the absence of α-ketoglutarate dehydrogenase activity suggest that the Krebs cycle is not in operation. 5. 5. The absence of opine dehydrogenases shows that the end products octopine, alanopine and strombine are not accumulated in the foot muscle under anaerobiosis. 6. 6. The high activity of malate dehydrogenase in the direction of malate formation in combination with the low activity of d-lactate dehydrogenase and the absence of opine dehydrogenases suggests that the former dehydrogenase is coupled 1:1 to glyceraldehyde-3-phosphate dehydrogenase.