title: Substrate specificity of uridine and purine nucleoside phosphorylases of the whole cells of Escherichia coli.
abstract: Substrate specificity of uridine and purine nucleoside phosphorylases of the whole cells of Escherichia coli BM-11 has been studied. Both enzymes reveal similar requirements to the structure and stereochemistry of uracil nucleosides and of the pentofuranose-1-phosphates, respectively, viz, a) modifications at C-3' decreased the substrate activity to a greater extent as compared with the same modifications at C-2'; b) substitution of a methyl group for one of the 5'-CH2 protons does not lead to essential alterations of the substrate activity of such analogs vs. the natural substrates - uridine and ribofuranose-1-phosphate, respectively. PNP exhibits a very broad specificity for the purine acceptor.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives*; D004926:Escherichia coli / Q000201:enzymology*; D010430:Pentosyltransferases / Q000378:metabolism*; D011683:Purine-Nucleoside Phosphorylase / Q000378:metabolism*; D013379:Substrate Specificity; D014529:Uridine / Q000031:analogs & derivatives*; D014543:Uridine Phosphorylase / Q000378:metabolism*
chemical_list: D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; D014543:Uridine Phosphorylase; D000241:Adenosine; D014529:Uridine