The Protein Denaturation by High Pressure
Changes of Optical Rotation and Susceptibility to Enzymic Proteolysis with Ovalbumin Denatured by Pressure
1962 年 52 巻 2 号 p. 67-71
詳細
1962 年 52 巻 2 号 p. 67-71
1. The denaturation of ovalbumin in aqueous solution by pressure up to 10, 000kg./cm.2, at temperatures of 20 and 30°C and at pH between 5.8 and 8.2 was studied with the solubility test, the susceptibility change to, enzymic proteolysis and the optical rotation change.
2. It was shown that the results obtained by above three methods were consistent within experimental error, and that the pressure denaturation of ovalbumin in aqueous solution started at about 5, 000kg./cm2 and completed at about 9, 000kg./cm2 after being compressed for 5 or 10 minutes.
3. Optical rotation change by pressure denaturation was considerably smaller than that of heat or urea denaturation.
4. Although the denaturation of oval-bumin by high pressure is accompanied by the relatively small change of optical rotation, , the denatured protein is fully precipitable in the solubility test and is fully hydrolysable by a proteolytic enzyme. Therefore the configurational change seems to be extensive, but it seems to cause the transformation to β-form.
5. In view of the negative volume of activation and the negative entropy of activation, it is of no doubt that the binding of water molecules by electrostriction plays an important role.
The authors wish to acknowledge the interest and encouragement of Prof. W. Jono and thank Drs. J. Osugi and T. Inagami for discussions as well as the generous assistance given by the staff of the Laboratories of Physical Chemistry in Kyoto University and Ritumeikan University. The expense of this study was defrayed in part by a grant from the Ministry of Education.
