FIG. 2.

Purine salvage and interconversion pathways in H. volcanii and H. halobium. The individual reactions are identified by numbers: 1, adenosine deaminase; 2, adenosine phosphorylase; 3, guanosine phosphorylase; 4, inosine phosphorylase; 5, inosine kinase; 6, guanosine kinase; 7, adenine phosphoribosyltransferase; 8, hypoxanthine(guanine) phosphoribosyltransferase; 9, guanine deaminase; 10, adenylosuccinate synthetase; 11, adenylosuccinate lyase; 12, IMP dehydrogenase; 13, GMP synthetase; 14, GMP reductase (found only in H. volcanii).