Saxholm H J, Pitot H C
Biochim Biophys Acta. 1979 May 24;562(3):386-99. doi: 10.1016/0005-2787(79)90103-5.
A high molecular weight complex containing aminoacyl-tRNA synthetases, peptidyl acetyltransferase, lipids and tRNA has been isolated from the 250,000 x g postmitochondrial supernatant from rat liver cells. Aminoacyl-tRNA synthetase activity directed towards arginine, aspartate, glutamine, glutamate, glycine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, and tyrosine is present. An endogenous pool of aminoacyladenylates is indicated by an ATP-32PPi exchange catalyzed by the native complex, which shows a dramatic increase after addition of ATP. Lysine is the only amino acid which greatly increases the exchange rate catalyzed by the native complex in vitro, whereas components of the denatured complex activate all the 13 amino acids in the presence of ATP. Six of the eight lipid fractions were glycolipids; cholesterol and cholesterol esters were absent. The extracted RNA has many characteristics of tRNA. These findings provide evidence for the organization of aminoacyl-tRNA synthetases in a complex with peptidyl acetyltransferase that also contains lipids and tRNA and that can be readily isolated from the cytosol of rat liver cells.
已从大鼠肝细胞250,000×g线粒体后上清液中分离出一种高分子量复合物，其含有氨酰 - tRNA合成酶、肽基乙酰转移酶、脂质和tRNA。该复合物具有针对精氨酸、天冬氨酸、谷氨酰胺、谷氨酸、甘氨酸、亮氨酸、赖氨酸、蛋氨酸、苯丙氨酸、脯氨酸、丝氨酸、苏氨酸和酪氨酸的氨酰 - tRNA合成酶活性。天然复合物催化的ATP - 32PPi交换表明存在氨酰腺苷酸的内源性池，添加ATP后该交换显著增加。赖氨酸是唯一能在体外极大提高天然复合物催化的交换速率的氨基酸，而变性复合物的组分在ATP存在下能激活所有13种氨基酸。八个脂质组分中有六个是糖脂；不存在胆固醇和胆固醇酯。提取的RNA具有许多tRNA的特征。这些发现为氨酰 - tRNA合成酶与肽基乙酰转移酶形成复合物提供了证据，该复合物还含有脂质和tRNA，并且可以很容易地从大鼠肝细胞的胞质溶胶中分离出来。
