title: Optimized method for determining free L-cysteine in rat plasma by high-performance liquid chromatography with the 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole conversion reagent.
abstract: The analytical method was optimized for L-cysteine (Cys) in rat plasma with co-existing L-cystine (Cyss). We observed that more than 100% Cyss in rat plasma was converted to Cys under typical conditions for the conversion with 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F). Another conversion reagent, 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole (ABD-F), was then employed, with which the reaction could be carried out at a low temperature without the use of a reducing reagent. Under the optimized conditions of 4 °C and pH 8.3, the conversion ratio of Cyss to Cys in rat plasma was as low as 5-7%. We determined the Cys concentration in plasma of the portal vein of rats that had been orally administered with Cys and Cyss by applying this method. The result indicated that Cys administration and also Cyss administration effectively increased the plasma Cys level. The method developed in this study is well suited for determining the thiol compounds in biological samples.
authors: Food for Life, Organization for Interdisciplinary Research Projects, The University of Tokyo, Tokyo, Japan.
authors: Lila
authors: L
authors: Otani
authors: Shinya
authors: S
authors: Ogawa
authors: Zhilei
authors: Z
authors: Zhao
authors: Kyoko
authors: K
authors: Nakazawa
authors: Shunsuke
authors: S
authors: Umehara
authors: Etsuro
authors: E
authors: Yoshimura
authors: Sue-Joan
authors: SJ
authors: Chang
authors: Hisanori
authors: H
authors: Kato
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003545:Cysteine / Q000008:administration & dosage / Q000097:blood*; D003553:Cystine / Q000008:administration & dosage / Q000097:blood*; D005456:Fluorescent Dyes / Q000737:chemistry; D005464:Fluorobenzenes / Q000737:chemistry; D008297:Male; D010069:Oxadiazoles / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005456:Fluorescent Dyes; D005464:Fluorobenzenes; D010069:Oxadiazoles; D003553:Cystine; C037802:7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate; C046364:4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole; D003545:Cysteine