title: ESR study of 5'-nucleotidase from bull seminal plasma.
abstract: 5'-Nucleotidase of bull seminal plasma has been spin labeled with the sulfhydryl reagent 3-maleimidoproxyl. ESR analysis reveals the presence of two classes of labeled sites. The first is characterized by a long spin label rotational correlation time, from which a protein diameter of about 70 A can be estimated, under the assumption of a spherical shape. The second class is characterized by a shorter correlation time of the covalently bound spin labels and binding of the substrate sodium thymidine 5'-monophosphate to 5'-nucleotidase results in a reduction of their mobility. Low-temperature ESR analysis shows that no paramagnetic ion is bound to the native protein.
authors.affiliation: Istituto Interfacoltá di Chimica Biologica, Universitá di Perugia, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Fini
authors.forename: A
authors.initials: A
authors.lastname: Floridi
authors.forename: S
authors.initials: S
authors.lastname: Cannistraro
mesh_terms: D015720:5'-Nucleotidase; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D008297:Male; D009708:Nucleotidases / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D012661:Semen / Q000201:enzymology*; D013113:Spin Labels
chemical_list: D003497:Cyclic N-Oxides; D013113:Spin Labels; C024516:N-(1-oxyl-2,2,5,5-tetramethyl-3-pyrrolidinyl)maleimide; D009708:Nucleotidases; D015720:5'-Nucleotidase