title: [Using of 4-thiouridine and 4-thiothymidine for pyrimidine nucleoside phosphorylase studing].
abstract: 4-Thiouridine and 4-thiothymidine were developed as efficient substrates for spectrophotometric determination of uridine phosphorylase and thymidine phosphorylase activity. 4-Thiouridine has maximum absorbance at 330 nm (pH 7.5). The change in extinction coefficient for 4-thiouridine/4-thiouracil, deltaepsilon is 3000 M(-1) x cm(-1). It appeared that 4-thiouridine is a good substrate for uridine phosphorylase with Michaelis-Menten constant 130 microM and kcat 49 s(-1). In the case of 4-thiothymidine/4-thiothymine deltaepsilon is even larger: 5000 M(-1) x cm(-1) at 336 nm.
authors.forename: N G
authors.initials: NG
authors.lastname: Panova
authors.forename: E V
authors.initials: EV
authors.lastname: Shcheveleva
authors.forename: K S
authors.initials: KS
authors.lastname: Alekseev
authors.forename: V G
authors.initials: VG
authors.lastname: Mukhortov
authors.forename: A N
authors.initials: AN
authors.lastname: Zuev
authors.forename: S N
authors.initials: SN
authors.lastname: Mikhaĭlov
authors.forename: R S
authors.initials: RS
authors.lastname: Esipov
authors.forename: D V
authors.initials: DV
authors.lastname: Chuvikovskiĭ
authors.forename: A I
authors.initials: AI
authors.lastname: Miroshnikov
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D010430:Pentosyltransferases / Q000737:chemistry / Q000378:metabolism*; D057845:Pyrimidine Phosphorylases; D013053:Spectrophotometry; D013379:Substrate Specificity; D013891:Thiouridine / Q000737:chemistry* / Q000378:metabolism; D013936:Thymidine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism
chemical_list: C414668:4-thiothymidine; D013891:Thiouridine; D010430:Pentosyltransferases; D057845:Pyrimidine Phosphorylases; D013936:Thymidine