Purification and Comparative Properties of a Pyrimidine Nucleoside Phosphorylase from Bacillus stearothermophilus

摘要: Abstract The pyrimidine-nucleoside:orthophosphate ribosyltransferase (EC 2.4.2.2), or pyrimidine nucleoside phosphorylase, from Bacillus stearothermophilus has been purified and compared with similar enzymes subtilis Escherichia coli. enzyme is stable at 60°, appears to be induced by either uridine thymidine, a molecular weight of approximately 78,000. Unlike phosphorylases most other sources, the thermophile catalyzes phosphorolysis both thymidine (apparent Km = 3.8 x 10-4 m) 2.5 and, in synthetic direction, does not distinguish between ribose 1-phosphate deoxyribose 1-phosphate. It differs E. coli B. many properties including weight, substrate specificity, thermostability, induction properties.