INTERRELATION BETWEEN THE FUNCTION OF HEME-PROTEINS AND THE STRUCTURAL MODIFICATIONS OF THEIR PROTEIN PARTS:IV. EFFECT OF SOME PROTEIN PERTURBATORS UPON THE CATALYTIC FUNCTION OF CATALASE
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The present experiment deals with the effects of perturbators such as sodium benzoate or salicylate upon the catalytic activity of catalase and the physical constitution of its protein molecule. The results can be summarized as follows:<br> 1. The catalatic activity of catalase decreased with increasing concentration of perturbators added to the system. Under the presence of a small amount of pyrogallol in the reaction system, the enzyme is active both catalatically and peroxidatically. Under such a condition, catalatic activity is recovered by the addition of benzoate. When pyrogallol was added to the system in concentrations equivalent to H<sub>2</sub>O<sub>2</sub>, so that the enzyme can behave prevalently as peroxidase, no recovery of catalatic activity was observable by the addition of perturbators.<br> 2. The peroxidatic activity of catalase was decreased by the addi-tion of perturbator to the system only under the condition in which H-donor was added lower than H<sub>2</sub>O<sub>2</sub>, so that catalase can behave simul-taneously as catalase as well as peroxidase. Under the condition in which, however, H-donor was added higher than H<sub>2</sub>O<sub>2</sub>, so that only peroxidatic activity prevails, the peroxidatic activity of catalase in-creased by the addition of lower concentration of perturbators.<br> 3. Tie structural modification of catalase molecule by perturbators proceeds stepwise with the increasing concentration of perturbators. In higher concentration range of perturbators, an absorption change of catalase could actually be observed, indicating the occurrence of a more progressed modification of the molecule. In this state, the catalytic activity of catalase was greatly decreased.<br> 4. It was proved that catalase shows an oxidative activity under certain experimental conditions. and Dr. R. Shukuya for their suggestions and kind advices during the course of this work.<br> The present work was supported by the subsidy of the Scientific Research Fund of the Ministry of Education (K. Kaziro).
- J Biochem (Tokyo)
J Biochem (Tokyo) 42(2), 99-109, 1955
The Japanese Biochemical Society