Kovaleva G K, Degtiarev S Kh, Favorova O O
Mol Biol (Mosk). 1979 Nov-Dec;13(6):1237-46.
3-Amino-1-chloro-indolwbutan-2-one (Trp-CH2Cl) was synthesized to be used for labeling the active site of tryptophanyl-tRNA-synthetase. Trp-CH2Cl irreversibly inhibits the beef pancreas tryptophanyl-tRNA synthetase activity. The inhibition rate was found to exhibit saturation concentration dependence typical for an affinity reagent. L-tryptophan and L-tryptophanyl adenylate protect the enzyme from inhibition. To determine the stoichiometry of inhibitor--protein binding 3H-label from NaB3H4 was incorporated into the modified enzyme. The molar ratio of inhibitor residues incorporated into the modified enzyme (dimeric molecule) is approximately 2. When one of the subunits of the enzyme was reversibly protected with relatively stable tryptophanyl adenylate, the modification of this enzyme led to the blocking of the other subunit (so called "one-site" enzyme). Some properties of the "one-site" enzyme obtained were studied.
合成了3-氨基-1-氯吲哚丁烷-2-酮（Trp-CH2Cl）用于标记色氨酰-tRNA合成酶的活性位点。Trp-CH2Cl不可逆地抑制牛胰色氨酰-tRNA合成酶的活性。发现抑制率表现出亲和试剂典型的饱和浓度依赖性。L-色氨酸和L-色氨酰腺苷酸可保护该酶免受抑制。为了确定抑制剂与蛋白质结合的化学计量比，将NaB3H4中的3H标记掺入修饰后的酶中。掺入修饰酶（二聚体分子）中的抑制剂残基的摩尔比约为2。当该酶的一个亚基被相对稳定的色氨酰腺苷酸可逆保护时，对该酶的修饰会导致另一个亚基被阻断（所谓的“单点”酶）。研究了所得“单点”酶的一些性质。
