Effect of Fasting on Calcium Activated Protease in Rat Skeletal Muscle

Abstract

Changes in calcium activated protease activity in rat skeletal muscle during fasting were studied. Cathepsin D activity in the same muscle was also measured. Calcium activated protease activity was significantly increased in the longissimus muscle of the back and the hind limb muscle during fasting. The increase in Cathepsin D activity was not as high as that of calcium activated protease. Calcium activated protease is generally supposed to degrade myofibrillar protein before the lysosomal enzymes (such as Cathepsin D) act in protein degradation due to fasting. It was indicated that calcium activated protease might take a significant role in enhancing the protein degradation resulting from fasting.