title: [Purification and properties of purine nucleoside phosphorylases from bird liver].
abstract: Chicken and pigeon liver PNPases differ in their isoelectric points (5.40 and 5.15), in their molecular weights (125,000 +/- 5,000; 78,000 +/- 5,000, determined on Sephadex G-200) and in their subunit molecular weight (62,000 +/- 10%; 75,000 +/- 10%, determined by sodium dodecil sulfate-polyacrylamide gel electrophoresis). The related molecular weights show a dimeric structure for the chicken liver enzyme and a monomeric structure for the pigeon liver enzyme. Activation energies are similar but differ in delta H values. Both PNPases are irreversibly inactivated by p-chloromercuribenzoate and 5,5'-dithiobis-(2-nitrobenzoic acid) when incubated with these reagents; inactivation can be reverted totally or partially by dithiothreitol and 2-mercaptoethanol.
mesh_terms: D000818:Animals; D002645:Chickens / Q000378:metabolism*; D010856:Columbidae / Q000378:metabolism*; D007526:Isoelectric Point; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D010430:Pentosyltransferases / Q000302:isolation & purification*; D011683:Purine-Nucleoside Phosphorylase / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D013045:Species Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology
chemical_list: D013439:Sulfhydryl Reagents; D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase
vernacular_title: Purificación y propiedades de purín nucleósido fosforilasas de hígado de ave.