AMPLIFICATION OF MYOADENYLATE DEAMINASE DURING EVOLUTION .2. PURIFICATION AND PROPERTIES OF THE ENZYME FROM 2 ELASMOBRANCH FISH, SCYLIORHINUS-CANICULA AND RAJA-CLAVATA

1. Muscle AMP deaminase was purified from two species of elasmobranch fish displaying different activities of the enzyme: the dogfish, Scyli orhinus canicula and the skate, Raja clavata. 2. The effects of pH, mo novalent cations, inorganic phosphate and nucleotide effectors were st udied on the two enzyme preparations. 3. While the physicochemical and regulatory properties of the AMP deaminase of skate muscle were very similar to those of the higher vertebrate muscle forms, the dogfish en zyme displayed properties of the non-muscular forms of higher vertebra tes. 4. These results are discussed in view of the genetic events whic h have led to the appearance of different AMP deaminase forms from a c ommon ancestral gene.