title: An external-sample liquid scintillation counting for 75Se and its application to selenoprotein detection.
abstract: An external-sample liquid scintillation (LS) counting for the gamma emitter 75Se has been developed. An expressly designed well-type LS vial and a 2,5-diphenyoxazole-1,4-bis(5-phenyl-2-oxazoyl)-benzene-xylene solution containing 35% tertrabutylzinn allow 75Se to be counted in a standard LS counter with counting efficiency up to 43.2%, much higher than that of conventional LS counting method. This external sample LS has a good count rate linearity and exhibits low background count rates. After in vivo labeling with [75Se]selenite, 75Se distributions and the Se-containing proteins present in tissues of male rat were investigated by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, external-sample LS and gamma-detector. Eight Se-containing proteins or protein subunits were detected to be Se-containing proteins or protein subunits in arterial wall, and their apparent molecular masses (Mr) were 76.4, 67.0, 57.4, 30.3, 25.4, 22.7, 21.7, and 15.1 kDa, respectively. In addition, eight 75Se-labeled proteins (Mr: 66.8, 57.0, 43.1, 30.0, 24.8, 19.8, 18.0, and 14.8 kDa) were found in brain homogenates, and nine 75Se-labeled proteins (Mr: 117.0, 78.0, 66.6, 57.2, 43.0, 38.1, 25.0, 20.1, and 18.0 kDa) were detected in testis homogenates. Some of them should be new biologically important selenoproteins that have not been identified so far.
authors.affiliation: Department of Chemistry, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
authors.forename: X H
authors.initials: XH
authors.lastname: Qu
authors.forename: K X
authors.initials: KX
authors.lastname: Huang
authors.forename: Z X
authors.initials: ZX
authors.lastname: Wu
authors.forename: S
authors.initials: S
authors.lastname: Zhong
authors.forename: L Q
authors.initials: LQ
authors.lastname: Deng
authors.forename: H B
authors.initials: HB
authors.lastname: Xu
mesh_terms: D000818:Animals; D001158:Arteries / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002073:Butanes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D008297:Male; D011506:Proteins / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012588:Scintillation Counting / Q000379:methods*; D012644:Selenium Radioisotopes / Q000737:chemistry* / Q000493:pharmacokinetics; D051140:Selenoproteins; D012680:Sensitivity and Specificity; D013737:Testis / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D002073:Butanes; D011506:Proteins; D012644:Selenium Radioisotopes; D051140:Selenoproteins