Modification of pyruvate kinase and lactate dehydrogenase in foot muscle of the sea mussel Mytilus galloprovincialis under anaerobiosis and recovery

Abstract

The modification of pyruvate kinase (PK) and lactate dehydrogenase (LDH) activity in foot muscle of the mussel Mytilus galloprovincialis during exposure to air and recovery in water was investigated. In the course of exposure to air, the activity of these enzymes measured at high and low substrate concentrations showed successive increases and decreases. Returning the mussels to water after exposure to air affected enzyme activity in a manner similar to anaerobiosis. When measuring at saturated concentrations of substrates and substrate and coenzyme for PK and LDH, respectively, the maximum activation of PK (37%) was observed at 4 h of animal exposure to air, and for LDH (67%) at 6 h exposure to air. During 24 h of exposure of animals to air, PK activity practically reached the stock level, while LDH was still activated (148%). The change in lactate dehydrogenase activity in mussel muscle during anoxia and recovery is described here for the first time. Variation in pyruvate kinase activity during exposure to air and recovery is linked to the alteration of half-maximal saturation constants and maximal velocity for both substrates. The possible role of reversible phosphorylation in the regulation of pyruvate kinase and lactate dehydrogenase properties is discussed.

Changes in lactate dehydrogenase and malate dehydrogenase activities during hypoxia and after temperature acclimation in the armored fish, Rhinelepis strigosa (Siluriformes, Loricariidae)

“…The results of K M values obtained for LDH and MDH of fishes acclimated to 20 o C and submitted to hypoxia suggest that naturally intense fluctuations in dissolved environmental oxygen may result in significant changes in enzyme activity, such as the ability of enzymes to respond to acute hypoxia. Lushchak et al (1997) found differences in enzyme activity throughout anaerobiosis and recovery of a sea mussel. Shaklee et al (1977) found significant differences in enzymatic activity for liver LDH and white muscle aldolases in fishes acclimated to different oxygen concentrations.…”

The effect of hypoxia and recuperation on carbohydrate metabolism in pacu (Piaractus mesotamicus)

“…A number of studies on many species have shown that fishes frequently respond to a change in environmental oxygen levels with changes within hematological parameters and alteration in physiological responses (Randall, 1993;Fernandes et al, 1995;Matsusaki et al, 1997). Enzymatic adaptations to hypoxia have already shown that there is a change in affinity of some enzymes involved in aerobic and anaerobic metabolism (Lushchak et al, 1997;Panepucci et al, 1998Panepucci et al, , 2000. Shaklee et al (1977) found significant differences in enzymatic activity for liver LDH and white muscle aldolases in fishes acclimated to different oxygen concentrations.…”