Gitlin G, Bayer E A, Wilchek M
Department of Biophysics, Weizmann Institute of Science, Rehovot, Israel.
Biochem J. 1988 Feb 15;250(1):291-4. doi: 10.1042/bj2500291.
Egg-white avidin was modified with the tryptophan-specific reagent 2-hydroxy-5-nitrobenzyl bromide. The complete loss of biotin-binding activity was achieved upon modification of an average of one tryptophan residue per avidin subunit. The identity of the modified residues was determined by isolating the relevant tryptic and chymotryptic peptides from CNBr-cleaved avidin fragments. The results demonstrate that Trp-70 and Trp-110 are modified in approximately equivalent proportions. It is believed that these residues are located in the active site of avidin and take part in the binding of biotin.
用色氨酸特异性试剂2-羟基-5-硝基苄基溴对蛋清抗生物素蛋白进行修饰。每个抗生物素蛋白亚基平均修饰一个色氨酸残基后，生物素结合活性完全丧失。通过从溴化氰裂解的抗生物素蛋白片段中分离相关的胰蛋白酶和胰凝乳蛋白酶肽段，确定了修饰残基的身份。结果表明，Trp-70和Trp-110的修饰比例大致相当。据信这些残基位于抗生物素蛋白的活性位点，并参与生物素的结合。
