MONROY A, ODDO A M
J Gen Physiol. 1951 Nov;35(2):245-53. doi: 10.1085/jgp.35.2.245.
The results presented in this paper give evidence of changes in solubility occurring in a protein fraction of the eggs of Arbacia lixula upon fertilization. The electrophoretic analysis indicates that it is only one part of one of the components of the KCl fraction that undergoes the change. However, under some experimental conditions (freezing and thawing of the KCl fraction or extraction of the whole eggs with water at room temperature) a larger portion of the KCl fraction, namely the whole group of components a and b, may be involved and undergoes coagulation. Therefore assuming that the results obtained on the extracts of frozen-dried fertilized eggs do reflect what actually occurs under natural conditions, we must also assume the existence of mechanisms controlling the extent of this change in the living eggs. The fact that in many cases one part or the whole of the sensitive fraction has been found to undergo an increase in solubility may suggest that the process of coagulation discovered by Mirsky is a two-step process. In the first step the sensitive fraction undergoes a change that makes it more soluble and then, when certain conditions are fulfilled, coagulation occurs. An alternative explanation could also be that the coagulated or coagulating fraction is attacked by the proteolytic enzyme that, as shown by Lundblad (1949, 1950), is activated on fertilization. This, however, seems to be less probable, as extraction was always carried out at 0 degrees C. and in as short a time as possible. However, further experiments are needed to decide whether the coagulation of the sensitive fraction is an actual occurrence under natural conditions. The results obtained with the eggs of Arbacia punctulata may cast some doubt on this assumption.
本文所呈现的结果证明了海胆（Arbacia lixula）卵的蛋白质部分在受精后溶解度发生了变化。电泳分析表明，只有氯化钾部分的一个组分中的一部分发生了这种变化。然而，在某些实验条件下（氯化钾部分的冻融或室温下水对全卵的提取），氯化钾部分的一大部分，即整个a和b组分组，可能会参与其中并发生凝聚。因此，假设从冻干的受精卵提取物中获得的结果确实反映了自然条件下实际发生的情况，我们还必须假设存在控制活卵中这种变化程度的机制。在许多情况下，已发现敏感部分的一部分或全部溶解度增加，这一事实可能表明米尔施（Mirsky）发现的凝聚过程是一个两步过程。第一步，敏感部分发生变化，使其更易溶解，然后，当某些条件满足时，发生凝聚。另一种解释也可能是，凝聚的或正在凝聚的部分受到蛋白水解酶的攻击，正如伦德布拉德（Lundblad，1949年，1950年）所表明的，这种酶在受精时被激活。然而，这似乎不太可能，因为提取总是在0摄氏度下尽可能短的时间内进行。然而，需要进一步的实验来确定敏感部分的凝聚在自然条件下是否实际发生。用紫海胆（Arbacia punctulata）卵获得的结果可能会对这一假设产生一些怀疑。
