用牛胰色氨酸 - tRNA连接酶对来自牛肉肝脏、酵母和大肠杆菌的tRNA Trp进行氨酰化。tRNATrp结合的化学计量学。
Aminoacylation of tRNA Trp from beef liver, yeast and E. coli by beef pancrease tryptophan-tRNA ligase. Stoichiometry of tRNATrp binding.
作者信息
Dorizzi M, Merault G, Fournier M, Labouesse J, Keith G, Dirheimer G, Buckingham R H
出版信息
Nucleic Acids Res. 1977 Jan;4(1):31-42. doi: 10.1093/nar/4.1.31.
The Michaelis constants and the maximum velocities in the aminoacylation reaction of tRNATrp from beef liver, yeast and E. coli by pure beef pancreas tryptophan-tRNA ligase show that this mammalian enzyme recognizes and charges the two eucaryotic tRNAs with the same efficiency. The rate of aminoacylation of the procaryotic tRNATrp by the enzyme is three orders of magnitude lower. The pH optimum of aminoacylation is 8 for both eucaryotic tRNAs. The optimum magnesium concentration is different. The rate is maximum when magnesium concentration is stoichiometric to ATP concentration for tRNATrp from beef liver and 10 mM above ATP concentration for tRNATrp from yeast. The number of binding sites on the enzyme for the two eucaryotic tRNAs has been measured by equilibrium filtration on Sephadex G-100 and found equal to two.
用纯牛胰色氨酸 - tRNA连接酶对来自牛肝、酵母和大肠杆菌的tRNATrp进行氨酰化反应时，其米氏常数和最大反应速度表明，这种哺乳动物酶识别两种真核tRNA并对其进行氨酰化的效率相同。该酶对原核tRNATrp的氨酰化速率要低三个数量级。两种真核tRNA氨酰化的最适pH均为8。最适镁离子浓度不同。对于牛肝tRNATrp，当镁离子浓度与ATP浓度化学计量相等时反应速度最快；对于酵母tRNATrp，当镁离子浓度比ATP浓度高10 mM时反应速度最快。通过在葡聚糖凝胶G - 100上进行平衡过滤测定了该酶上两种真核tRNA的结合位点数，发现其等于两个。
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