Amat E, Palou J, Garcia Blanco F
Enzyme. 1985;34(2):83-93. doi: 10.1159/000469367.
The different effects induced by AMP and its analogues on the tertiary structure and the coenzyme environment of phosphorylase b were studied by titration of the slowly reacting thiol groups and by quenching of the coenzyme fluorescence, respectively, to determine the possible differences that activate phosphorylase b. The following results were obtained: The coenzyme environment depends upon the nucleotide studied. AMP, when bound to its first site, opens the coenzyme pocket. The slow cysteines were shielded by the nucleotides against their DTNB titration depending on the nucleotide studied. The enzyme difference spectra in presence of the nucleotide showed that the negative band of 260 nm is similar for all nucleotides possessing the same base, but the positive band obtained in the presence of AMP was diminished when other nucleotides were present.
通过滴定反应缓慢的巯基以及猝灭辅酶荧光，分别研究了AMP及其类似物对磷酸化酶b三级结构和辅酶环境的不同影响，以确定激活磷酸化酶b的可能差异。得到以下结果：辅酶环境取决于所研究的核苷酸。AMP与第一个位点结合时，会打开辅酶口袋。根据所研究的核苷酸不同，核苷酸会保护反应缓慢的半胱氨酸不被DTNB滴定。核苷酸存在时的酶差异光谱表明，所有具有相同碱基的核苷酸在260nm处的负带相似，但当存在其他核苷酸时，AMP存在时获得的正带会减弱。
