胰蛋白酶的失活：III. 自发失活。

THE INACTIVATION OF TRYPSIN : III. SPONTANEOUS INACTIVATION.

Laboratories of The Rockefeller Institute for Medical Research.

J Gen Physiol. 1922 Jan 20;4(3):261-74. doi: 10.1085/jgp.4.3.261.

Abstract

The rate of inactivation of purified trypsin solutions approximates closely that demanded by the monomolecular formula. The more carefully the solution is purified the closer the agreement with the formula. 2. The products formed by the action of trypsin on proteins renders the trypsin more stable. Gelatin and glycine have no effect. 3. The rate of inactivation of trypsin solutions containing these products does not follow the course of a monomolecular reaction but becomes progressively slower than the predicted rate. 4. The protective action of these substances is much greater if they are added all at once at the beginning of the experiment than if they are added at intervals. These observations may be quantitatively accounted for by the hypothesis that a compound is formed between trypsin and the inhibiting substance which is stable as well as inactive, and that the rate of decomposition depends on the amount of uncombined trypsin present. 5. Trypsin is most stable at a pH of 5 and is rapidly destroyed in strongly acid or alkaline solution. 6. The protective effect of the inhibiting substances is small on the acid side of pH 5, increases from pH 5 to 7, and then remains approximately constant.

摘要

纯化的胰蛋白酶溶液的失活动率与单分子公式所要求的非常接近。溶液纯化得越仔细，与公式的符合程度就越高。
胰蛋白酶对蛋白质的作用所产生的产物使胰蛋白酶更加稳定。明胶和甘氨酸没有影响。
含有这些产物的胰蛋白酶溶液的失活动率并不遵循单分子反应的过程，而是变得比预测的速度越来越慢。
如果这些物质在实验开始时一次性全部添加，它们的保护作用比间隔添加时要大得多。这些观察结果可以用假设来定量解释，即胰蛋白酶和抑制物质之间形成一种稳定但无活性的化合物，并且分解速度取决于未结合的胰蛋白酶的量。
胰蛋白酶在 pH 值为 5 时最稳定，在强酸或强碱溶液中迅速被破坏。
抑制物质的保护作用在 pH 值 5 的酸性侧较小，从 pH 值 5 增加到 7，然后大致保持不变。