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已有证据表明,OH自由基是参与水溶浪中间接放射诱导的某些酶灾活的主要的自由基。OH自由基能被卤化物或一些伪卤化物(X)清除:X~-+·OH→X+OH~-X~-+X~-通常形成二聚有由基阴离子气(X_2~-)。这些无机自由基阴离子选择性地与酶的氨基酸残基作用。因此,自由基反应可用于鉴定决定酶活性的某些氨基酸。作者等以前曾证明(SCN)_2~-阴离子自由基能与色氨酸起反应。并且SCN~-与产生的色氨酸阴离子(TrpH~+,酸性环境下)之间的平衡是可逆的。现在,作者又用对酸极其稳定的酶-胃蛋白酶试验,发现(SCN)_2~-对胃蛋白酶的灭活作用取决于
There is evidence that OH radicals are the major free radicals involved in the activity of certain enzymes induced by indirect radiation in sodas. OH radicals can be eliminated by halides or pseudo-halides (X): X ~ - + · OH → X + OH ~ -X ~ - + X ~ . These inorganic free radical anions selectively interact with the amino acid residues of the enzyme. Therefore, free radical reactions can be used to identify certain amino acids that determine enzyme activity. The authors have previously demonstrated that (SCN) 2 ~ - anion free radicals can react with tryptophan. And the balance between SCN ~ - and tryptophan anion (TrpH ~ +, acidic environment) is reversible. Now, with the exception of the acid-pepsin assay, which is extremely stable to acids, the authors found that the inactivation of pepsin by (SCN) 2 ~ depends on