Mechanism of action of 5'-nucleotidase.

The enzyme 5’-nucleotidase was originally discovered in the venom of snakes (1) and later shown to be present in mammalian tissues (2-5) and bull seminal plasma (6). It has recently been extensively purified and characterized by Heppel and Hilmoe (7). The enzyme was shown to hydrolyze 5’-nucleotides rapidly, ribose-5-phosphate slowly, and other phosphate esters extremely slowly, if at all. Because of its importance in nucleotide metabolism and its interesting specificity pattern, a study of the mechanism of action of the enzyme was initiated. In order to determine whether carbon-oxygen or phosphorus-oxygen bond rupture occurred during the hydrolytic action, the hydrolysis of adenosine-5-phosphate was followed in Hz018 (see Equation 1). After the cleavage point was determined, exchange experiments of adenosine-C14,