INTERRELATION BETWEEN THE FUNCTION OF HEMEPROTEINS AND THE STRUCTURAL MODIFICATIONS OF THEIR PROTEIN PARTS
III. EFFECTS OF SODIUM SALICYLATE AND BENZOATE UPON THE REACTION OF CHOLEGLOBIN FORMATION
1954 年 41 巻 4 号 p. 503-512
詳細
1954 年 41 巻 4 号 p. 503-512
Studies were made on the changes of catalytic activities of hemoglobin following the structural modification of the latter induced by sodium salicylate or benzoate with special reference to their influences upon the process of choleglobin formation in the hemoglobin-ascorbic acid-O2 system. The results are summarized as follows:
1. Reaction rate of choleglobin formation, as well as of O2 uptake, increased with increasing concentrations of salicylate or benzoate added. But, when the concentration of the perturbators increased over a definite limit, the rate decreased again.
2, The perturbation of hemoglobin molecule seemed to proceed stepwise following the increase of salicylate or benzoate concentrations. There may most probably be a secondary stable state of hemoglobin molecule.
3. The concentration of salicylate or benzoate favorable to promote the choleglobin formation was proved to be far lower than that either to bring about the spectroscopically demonstrable grade-of perturbation of hemoglobin molecule or to promote the rate of HbO2 autoxidation.
4. The temperature effect on the reaction of choleglobin formation under the presence of perturbators was much greater than that without perturbators.
5. From all of the results of the present experiments, it may be postulated that the above mentioned effects of benzoate and salicylate are due to the protein denaturation of a milder grade caused by them. Our previous assumption of an active intermediate compound x possibly produced in the process of choleglobin formation from hemoglobin may be accepted to be justifiable on the basis of our present experimental evidences.
The authors wish to thank Prof. K. Kaziro for his continous guidance and encouragement during the course of the present studies.
This work was aided by a Grant from the Scientific Research Fund of the Ministry of Education (K. Kaziro).
