Properties of a non-specific nucleotidase in the membrane of rabbit red cells.

A non-specific nucleotidase was found in rabbit red blood cell membrane and, using 5'-AMP as substrate, several kinetic parameters for the enzyme were determined. Rabbit red cell ghosts catalyzed the hydrolysis of a wide spectrum of nucleoside 5'-, 3'- and 2'-monophosphates and a limited number of non-nucleotide substrates. All these activities were heat inactivated at the same rate, suggesting that they are the result of catalysis by the same enzyme. The nucleotidase was not dependent on K+ or Mg2+ and was also insensitive to ouabain. Its specific activity and other kinetic parameters were identical in preparation of membranes from both reticulocytes and the mature erythrocytes.