GTP‐binding proteins in human platelet membranes serving as the specific substrate of islet‐activating protein, pertussis toxin

FEBS Letters

Itoh, Hiroshi¹  Kaziro, Yoshito¹  Ui, Michio²  Katada, Toshiaki⁴  Nagata, Koh-ichi³  Nozawa, Yoshinori³  Tohkin, Masahiro⁴ 

[1] Institute of Medical Science, University of Tokyo, Tokyo 108, Japan;Department of Physiological Chemistry, Faculty of Pharmaceutical Science, University of Tokyo, Tokyo 113, Japan;Department of Biochemistry, Gifu University School of Medicine, Gifu 500, Japan;Department of Life Science, Faculty of Science, Tokyo Institute of Technology, Yokohama 227, Japan

关键词: GTP-binding protein;    Islet-activating protein;    Pertussis toxin;    (Human platelet);   

DOI  :  10.1016/0014-5793(88)80182-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Two GTP-binding proteins serving as the specific substrate of islet-activating protein (IAP), pertussis toxin, were purified from human platelet membranes as heterotrimers with an αβγ-subunit structure. The α of the major IAP substrate had a molecular mass of 40 kDa and differed from that of G_{i 1} or G_o previously purified from brain membranes. The partial amino acid sequences of the 40 kDa α completely matched with the sequences which were deduced from the nucleotide sequences of the human G_{i 2} α gene. On the other hand, the α of the minor IAP substrate purified from human platelets was about 41 kDa and cross-reacted with an antibody raised against α of brain G_{i 1} (G_{i 1} α). These results indicate that the major IAP substrate present in human platelet membranes is a product of the G_{i 2} α gene.

【 授权许可】

Unknown