MEMBRANE-BOUND 5'-NUCLEOTIDASE NUCLEOSIDE PHOSPHOTRANSFERASE FROM BACILLUS-CEREUS

1. A search for nucleoside phosphotransferase activity in Bacillus cer eus led to the following results: (i) The phosphotransferase activity was associated with a membrane bound 5'-nucleotidase. (ii) The enzyme phosphorylates both purine and pyrimidine nucleosides as well as 2',3' -dideoxyinosine. (iii) The enzyme was inhibited by adenylic nucleotide di- and triphosphates, and its nucleotidase activity was increased in the presence of inosine as phosphate acceptor. 2. Bacterial and verte brate 5'-nucleotidases with phosphotransferase activity differ for sev eral characteristics, such as cellular location, substrate specificity , magnesium requirement and regulation.