Ranu R S, Kaji A
J Bacteriol. 1971 Jul;107(1):53-60. doi: 10.1128/jb.107.1.53-60.1971.
The effect of various sulfhydryl reagents on the ribosomes of Bacillus subtilis was studied. The 70S ribosomes were completely dissociated into 30S and 50S subunits by appropriate concentrations of p-chloromercuribenzoic acid (PCMB) and 5,5'-dithio-bis-(2-nitro-benzoic acid). The N-ethylmaleimide and iodoacetamide failed to dissociate the ribosomes even at relatively high concentrations. The rate of dissociation of ribosomes by PCMB varied with the concentration of ribosomes. A progressive decrease in the rate of dissociation was observed as the concentration of ribosomes in the reaction mixture was increased. The PCMB-induced ribosomal subunits were unable to reassociate into 70S monomers unless they were dialyzed against buffer containing beta-mercaptoethanol. On the average, four molecules of PCMB per 70S ribosome and two molecules of PCMB per each 30S and 50S subunit were bound. The number of PCMB molecules bound per ribosome did not change with increasing concentrations of PCMB, even though higher concentrations of PCMB resulted in dissociation of ribosomes into subunits.
研究了各种巯基试剂对枯草芽孢杆菌核糖体的影响。通过适当浓度的对氯汞苯甲酸（PCMB）和5,5'-二硫代双（2-硝基苯甲酸），70S核糖体可完全解离为30S和50S亚基。即使在相对较高的浓度下，N-乙基马来酰亚胺和碘乙酰胺也未能使核糖体解离。PCMB使核糖体解离的速率随核糖体浓度而变化。随着反应混合物中核糖体浓度的增加，观察到解离速率逐渐降低。PCMB诱导的核糖体亚基除非用含有β-巯基乙醇的缓冲液透析，否则无法重新结合成70S单体。平均而言，每70S核糖体结合四个PCMB分子，每个30S和50S亚基结合两个PCMB分子。尽管较高浓度的PCMB会导致核糖体解离为亚基，但每个核糖体结合的PCMB分子数量不会随PCMB浓度的增加而改变。
