Photoaffinity labeling of thiamin‐binding component in yeast plasma membrane with [3H]4‐azido‐2‐nitrobenzoylthiamin

FEBS Letters

Iwashima, Akio¹  Kawasaki, Yuko¹  Nishimura, Hiroshi¹  Sempuku, Kenji¹  Nosaka, Kazuto¹ 

[1] Department of Biochemistry, Kyoto Prefectural University of Medicine, Kamikyoku, Kyoto 602, Japan

关键词: Thiamin binding;    Plasma membrane;    Photoaffinity labeling;    (Saccharomyces cerevisiae);   

DOI  :  10.1016/0014-5793(89)81080-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

When prepared from Saccharomyces cerevisiae through an acid precipitation at pH 5.0 for a crude particulate fraction obtained by mechanical agitation of yeast protoplasts with glass beads, the plasma membranes have more remarkable binding quantities of [¹⁴C]thiamin (K _d, 51 nM; B _max, 263 pmol per mg of protein) compared with our previously prepared membranes [(1986) Experientia 42, 607–608]. Photoaffinity labeling of these yeast plasma membranes with [³H]4-azido-2-nitrobenzoylthiamin resulted in the covalent modification of a membrane component with an apparent molecular mass of 6–8 kDa. The extent of its labeling was markedly decreased by previous addition of thiamin. This result suggests that the small membrane component (6–8 kDa) takes part in the thiamin binding of thiamin carrier protein(s) in yeast plasma membranes.

【 授权许可】

Unknown