5’-adenylic Acid Deaminase

In 1928, Schmidt (1) first described the presence of 5’-adenylic acid deaminase in muscle. He succeeded in separating this enzyme from adenosine deaminase and in isolating inosinic acid and ammonia as products of the reaction. He also reported that it specifically deaminated 5’-adenylic acid. In 1947, Kalckar (2) described two methods for the preparation of this enzyme and introduced a spectrophotometric method for the determination of the enzyme activity. A procedure for purifying this enzyme, based on a combination of the procedures of Schmidt and Kalckar and supplemented by the paper chromatographic technique for enzymes as described by Mitchell et al. (3), was developed by Nikiforuk and Colowick (4). Cytologically, the deaminase is located in the myofibrillar nuclear component of skeletal muscle (5). This enzyme exists not only in skeletal muscle but also in the water-soluble fraction of heart muscle, smooth muscle, liver, and kidney (6-9), although these activities are never as great as that of skeletal muscle. The deaminase is present as a complex with myosin (10-17). The separation of this enzyme from myosin by heat treatment was first reported by Engelhardt et al. (18) and Lyubimova and Matlina (19), and has been confirmed by the present author (20) and Locker (21) in detail. Engelhardt et al. claimed that this enzyme had globulin properties and required a cofactor which was lost during the prolonged dialysis. In the present paper, a method developed from a preceding report (20) is described for the isolation of crystalline deaminase from rabbit skeletal muscle.