EFFECT OF MYOGLOBIN ON THE MUSCLE LIPASE SYSTEM

The effect of different concentrations of myoglobin on the enzyme syst ems involved in lipid degradation were determined. Lipases, including both acid and neutral lipases and acid phospholipase, were inhibited b y myoglobin. The neutral lipase was more susceptible to the inhibitory effect of myoglobin (35% of its initial activity at 1 mg/mL of myoglo bin), followed closely by acid phospholipase; acid lipase activity was affected to a lesser extent (less than 20% inhibition). This inhibiti on was also observed on the esterase activities, being greater on the neutral esterase activity (38% of its initial activity at I mg/mL of m yoglobin) than on the acid one. lit view of these results, myoglobin c ould be considered as an endogenous inhibitor which would determine th e lipolytic activity in different type of muscles and therefore, the r ate of generation of the free fatty acids.