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In the previous paper, the ATPase accelerating peptides were found to be distinct from the vasoactive and vasodilatory peptides in the same hydrolysate. This work was undertaken to isolate the ATPase accelerating peptide from the fur seal muscle hydrolysate. Minced skeletal muscle of fur seal was digested with protease and the resulting hydrolysate was fractionated with 90%ethanol. The obtained precipitate and the effective agent was fund only in the precipitate. By continuous flow electrophoresis, the was divided into five major fractions, each of which was examind for accelerating effect on ATPase by two different methods, i.e., inorganic phosphate determination and pH-stat method. Among the five electrophoretic fractions, the second fraction E2 migrating to the anode showed the best accelerating effect, while the other fractions were less accelerative. Also the possible of Ca ions was refuted. E2 was also examined for physiological activity by kymographic recording of the contraction of rat intestine smooth muscle and showed an effect which is revealed by a contraction preceded by a slight relaxation. Thin layer chromatography revealed that there are more than two peptide components in fraction E2.

2′,3′-Cyclic nucleotide 3′-phosphohydrolase has been demonstrated in human erythrocyte membranes. The properties of 2′,3′-cyclic nucleotide 3′-phosphohydrolase in erythrocyte membranes were similar to those of the brain enzyme with respect to pH optimum, substrate specificity and effects of metal ions. The estimation of 2′,3′-cyclic nucleotide 3′-phosphohydrolase in various stages of membrane preparation showed that the enzyme in erythrocytes is exclusively associated with the membranes.

In an analysis of the gastrocnemius muscle, the microsomal fraction showed the highest cholinesterase (ChE) activity. The ChE activity of all fractions decreased to a greater extent after strong nerve crushing than after weak crushing. This change in the activity in the microsomal fraction was the most marked change observed. Although in the analysis of the soleus muscle the ChE activity was measured only in the homogenate and in the microsomal fraction, the results were the same as those obtained with the gastrocnemius. A preparation of vitamins B1, B2, and B12 (B complex) had little effect on the ChE activity in the gastrocnemius muscle. In the soleus muscle on the lesion side, the B complex increased the ChE activity to some extent after nerve crushing, but such was not significant. However, the B complex signifiicantly increased this activity in the soleus on the intact side. In the soleus muscle, strong nerve crushing induced more marked muscle atrophy than weak crushing. On the other hand, no significant difference was found in the gastrocnemius. Effects of the B complex on muscle atrophy were found in the soleus, but not in the gastrocnemius. These results suggest that the ChE activity in the microsomal fraction containing sarcoplasmic reticulum reflects the nervous disorders clearly, and that the B complex increases the ChE activity and muscle weight in the soleus, but not in the gastrocnemius muscle.