STUDIES ON THE INTERACTION BETWEEN PYRIDINE-HEMIN AND HYDROGEN PEROXIDE OR OXYGEN:II. THE FACTORS AFFECTING THE PROCESS OF VERDOHEMOCHROME FORMATION

J-STAGE

Description

The effects of pH, and the concentration of ascorbic acid and copper ion on the process of verdohemochrome formation were studied in its each stage by means of spectrophotometric method. The results obtained are conclusively summarized as follows.<br> 1. Both the decomposition of pyridine-hemin into 630-compound and the conversion of 630-compound into verdohemochrome are the processes of the autocatalytic oxidations in their nature, connected with their catalytic activities.<br> 2. A certain reductant can be indispensable for the 630-compound formation. It is difficult, however, to determine whether the Fe++ or the Fe+++ state of pyridine-hemin is more responsible for the process. 3. Verdohemochrome can be produced from the Fe+++ state of 630-compound by the direct action of molecular oxygen without any reductant.<br> 4. If H2O2 is produced excessively, for example, by higher concentration of ascorbic acid or by the addition of copper ion, the by-product formation will increase through a side reaction.<br> 5. On the basis of the experimental evidences hitherto obtained including those from our previous information a scheme on the re-action processes in the pyridine-hemin-ascorbic acid-oxygen system is hypothetically presented.<br> The present investigation was supported by the subsidy of the Science Research Fund of the Ministry of Education.

Journal

  • J Biochem (Tokyo)

    J Biochem (Tokyo) 39 (1), 63-76, 1952

    The Japanese Biochemical Society

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