Inanobe A, Shibasaki H, Takahashi K, Kobayashi I, Tomita U, Ui M, Katada T
Department of Life Science, Faculty of Science, Tokyo Institute of Technology, Yokohama, Japan.
FEBS Lett. 1990 Apr 24;263(2):369-72. doi: 10.1016/0014-5793(90)81416-l.
Recently we reported there were at least four types of G0 or G0-like proteins in bovine brain membranes based on their elution profiles from Mono Q columns and their immunological reactivities; one of the proteins was purified as an alpha-monomeric form, and the others as alpha beta gamma-trimers. The four proteins, of which alpha-subunits were confirmed to be a family of G0-type by an immunoblot analysis, were thus referred to as alpha (0)1, G(0)2, G(0)3 and G(0)4, respectively, in order of their elutions from the column. Immunostained peptide mappings arising from proteolytic digestions of the four alpha-subunits, together with their fragmentation patterns containing radiolabeled ADP-ribose that had been incorporated by pertussis toxin-catalyzed ADP-ribosylation, suggested that the four G0-alpha were classified into either of two groups such as alpha (0)1 and G(0)2-alpha, or G(0)3-alpha and G(0)4-alpha. The kinetic parameters of their GTPase activities, however, revealed that there were different properties between alpha (0)1 and G(0)2-alpha or G(0)3-alpha and G(0)4-alpha. Thus, the four G0-type proteins appeared to be different entities from one another.
最近我们报道，基于牛脑膜蛋白从Mono Q柱上的洗脱图谱及其免疫反应性，牛脑膜中至少存在四种类型的G0或类G0蛋白；其中一种蛋白被纯化呈α单体形式，其他的则为αβγ三聚体形式。通过免疫印迹分析确认α亚基为G0型家族的这四种蛋白，因此按照它们从柱上洗脱的顺序，分别被称为α(0)1、G(0)2、G(0)3和G(0)4。四种α亚基经蛋白酶消化产生的免疫染色肽图谱，以及它们含有经百日咳毒素催化的ADP核糖基化掺入的放射性标记ADP核糖的片段化模式，表明这四种G0-α可分为两组，如α(0)1和G(0)2-α，或G(0)3-α和G(0)4-α。然而，它们GTP酶活性的动力学参数显示，α(0)1与G(0)2-α之间，或G(0)3-α与G(0)4-α之间存在不同特性。因此，这四种G0型蛋白似乎彼此是不同的实体。
