Aspects of anaerobic metabolism in Anodonta cygnea L.

Abstract

1. After 6 days of anoxia A. cygnea had produced 1.0 µmole succinate, 2.7 µmole propionate and 1.7 µmole acetate/g of total soft tissue (wet). In addition, 0.35 µmole glutamate had disappeared. No other changes were detectable. 2. Concentrations of anaerobic end products and of amino acids differed from organ to organ. Large portions of all end products produced were present in the fluids within the animal. 3. Acetate and propionate were also excreted into the surrounding water. 4. In all tissues examined the activity ratio of pyruvate kinase and phosphoenolpyruvate carboxykinase was high 5. The [PEP]₀.₅ of pyruvate kinase was relatively low (0.04-0.05 mM at pH 7.5), and the enzyme is not strongly inhibited at decreased pH or in the presence of alanine. 6. Anaerobiosis influences this enzyme by decreasing the activity at low substrate concentration.