Kakhniashvili D G, Smailov S K, Gavrilova L P
Biokhimiia. 1980 Nov;45(11):1999-2012.
It has been found that preparations of Escherichia coli (MRE-600) ribosomes can display GTPase and ATPase activities independent of elongation factors EF-Tu and EF-G. The GTPase and ATPase are localized on ribosomal 50S subparticles, whereas 30S subparticles are free of the activities and do not stimulate them upon association with the 50S subparticles to form complete ribosomes. The GTPase and ATPase can be removed from the ribosomes and their 50S subparticles by treatment with 1 M NH4Cl or 50% ethanol in the cold. Ribosomal preparations freed from the factor-independent GTPase and ATPase retain their basic functional features. The data obtained do not permit to solve finally whether the factor-independent GTPase and ATPase revealed are components of ribosomes or represent a contamination rather firmly bound to the ribosomes. However, in any case this finding can contribute to an uncoupled hydrolysis of GTP and should be considered when studying the stoichiometry of triphosphate expenditure in the process of ribosomal protein synthesis.
已发现大肠杆菌（MRE - 600）核糖体制剂可表现出GTP酶和ATP酶活性，且这些活性独立于延伸因子EF - Tu和EF - G。GTP酶和ATP酶定位于核糖体50S亚基上，而30S亚基则没有这些活性，并且在与50S亚基结合形成完整核糖体时也不会刺激这些活性。通过在低温下用1 M NH4Cl或50%乙醇处理，可从核糖体及其50S亚基中去除GTP酶和ATP酶。去除了不依赖因子的GTP酶和ATP酶的核糖体制剂保留了其基本功能特征。所获得的数据最终无法确定所揭示的不依赖因子的GTP酶和ATP酶是核糖体的组成部分还是代表与核糖体紧密结合的污染物。然而，无论如何，这一发现可能有助于GTP的非偶联水解，并且在研究核糖体蛋白质合成过程中三磷酸消耗的化学计量时应予以考虑。
