Purification and characterization of two GTP‐binding proteins of 22 kDa from human platelet membranes

FEBS Letters

Nagata, Koh-ichi¹  Nozawa, Yoshinori¹ 

[1]Department of Biochemistry, Gifu University School of Medicine, Tsukasamachi-40, Gifu 500, Japan

关键词: GTP-binding protein;    Low-molecular mass;    ras p21;    (Human platelet);    AppNHp;    adenosine 5′-(β;    γ-imido)triphosphate;   

DOI  :  10.1016/0014-5793(88)80232-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Two GTP-binding proteins (G-proteins) of 22 kDa were purified to near homogeneity from a sodium cholate extract of human platelet membranes by successive chromatographies on DEAE-Sephacel, Ultrogel AcA-44, phenyl-Sepharose CL-4B, Mono Q HR5/5 and hydroxyapatite columns. They bound maximally 0.89 mol of [³⁵S]guanosine 5′-(3-O-thio)triphosphate per mol of both purified proteins, and this binding was inhibited by GTP and GDP but not by ATP and AppNHp. Their molecular masses were somewhat lower than that of ras p21 and they were not recognized by an anti-v-Ki-ras p21 antibody. These results indicate that human platelet membranes contain at least two low-molecular-mass G-proteins distinct from ras p21, in addition to the heterotrimeric G-proteins, the α-subunits of which possess molecular mass values of about 40 kDa.

【 授权许可】

Unknown