PURIFICATION AND CHARACTERIZATION OF AMP-DEAMINASE FROM TROUT WHITE MUSCLE

AMP-deaminase was purified from trout white muscle and some of its properties were studied. The electrophoretically homogenous enzyme had monomer molecular weight 71,600 +/- 550 and specific activity 200-500 U/mg protein. The enzyme is activated in the acidic physiological range through a decrease in K-m for substrate. ADP and ATP activated and GTP inhibited the enzyme. It was also inhibited by IMP, a characteristic which has not been previously described. Changing the pH within the physiological range (6.6-7.3) did not modify the influence of ATP, GTP, and IMP on the properties of the AMP-deaminase, but the activation of enzyme by ADP was sensitive to pH. The possible regulation of fish muscle AMP during intensification of metabolism is discussed.