The chemical characterization of calf brain microtubule protein subunits.
The chemical characterization of calf brain microtubule protein subunits.
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小牛脑微管蛋白亚基的化学表征。
DOI：
10.1016/s0021-9258(19)43386-3
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发表时间：
1973
期刊：
影响因子：
--
通讯作者：
S. N. Timasheff
中科院分区：
文献类型：
--
作者：
James C. Lee;R. Frigon;S. N. Timasheff
小牛脑微管蛋白（微管蛋白）的化学特性。氨基酸分析和氢离子滴定在5 M盐酸胍产生的化学组成类似的微管蛋白从其他来源。NH 2-末端残基被鉴定为甲硫氨酸。当蛋白质在8 murea中变性和还原时，在尿素存在下的凝胶电泳中观察到两条明显的蛋白质带，表明存在两个不同的亚基。微管蛋白亚基的分子量由多种技术确定，包括在6 m胍盐酸盐中的沉降平衡和光散射，十二烷基硫酸钠凝胶电泳，在6 m胍盐酸盐存在下的琼脂糖柱上的色谱，以及在6 m胍盐酸盐中的S-羧甲基化的还原蛋白质的粘度。所有方法得到的平均分子量值均为（54，000 ± 1，000），无论测量是否使用还原剂，均表明存在的所有二硫键均为链内二硫键。
Calf brain microtubule protein (tubulin) was characterized chemically. Amino acid analysis and hydrogen ion titration in 5mguanidine hydrochloride yielded a chemical composition similar to that of tubulin from other sources. The NH2-terminal residue was identified as methionine. When the protein was denatured and reduced in 8murea, two distinct protein bands were observed in gel electrophoresis in the presence of urea, suggesting the existence of two nonidentical subunits. The molecular weight of the tubulin subunits was determined by a variety of techniques, including sedimentation equilibrium and light scattering in 6mguanidine hydrochloride, sodium dodecyl sulfate gel electrophoresis, chromatrography on an agarose column in the presence of 6mguanidine hydrochloride, and viscometry ofS-carboxymethylated, reduced protein in 6mguanidine hydrochloride. All methods yielded an average molecular weight value of (54,000 ± 1,000), whether the measurements were done with or without reducing agents, indicating that all disulfide bonds present are intrachain.