INDICATOR ENZYME ASSAYS .1. ADENYLATE DEAMINASE - PRINCIPLES AND APPLICATION TO HUMAN-MUSCLE BIOPSIES AND BLOOD-CELLS

A multisample spectrophotometric assay for adenylate deaminase in the visible wavelength range has been developed, and the principles involved in optimizing assay conditions have been summarized. The assay was found to exhibit excellent stability characteristics, and was suitable for assay of crude (or purified) enzyme in a variety of tissues, including erythrocyte lysates. The assay has been tested with a number of substrate analogs, activators, and inhibitors, and by comparison with an ultraviolet absorption assay. The apparent Km for purified rabbit (and crude mouse) muscle adenylate deaminase was 0.4 mm. The assay was used to delineate an optimal extraction medium for the human muscle enzyme, which was then used to confirm the existence of myoadenylate deaminase deficiency and a probable carrier state. The assay was also used to compare the relative specific activities of muscle, granulocytes, lymphocytes, platelets, and erythrocytes, which were approximately 100, 20, 3, 2, 1. © 1979.