ACTIONS OF RADIATIONS ON ENZYMES. III. THE INACTIVATING MECHANISM OF SULPHYDRYL ENZYMES BY $gamma$-IRRADIATION (ENGLISH TEXT)
Among the oxidizing agents produced by irradiation of water by gamma rays, OH and O/sub 2/H radicals and hydrogen peroxide were proved to be effective in causing inactivation of the enzymes whose sulphydryl groups are responsible for their activity. In the case of yeast alcohol dehydrogenase, it was shown that 46.5% of the inactivation was caused by OH radicals, 29.3% by O/sub 2/H radicals, and 24.2% by hydrogen peroxide. When cysteine in aqueous solution was irradiated by gamma rays the amount of sulphydryl groups of cysteine molecule was found to decrease linearly with dose. It was demonstrated that the amounts of sulphydryl groups in yeast AOH and liver glutamic dehydrogenase decreased with the increase of dose. In the case of urease, irradiation caused a lowering of enzyme activity in proportion to the decrease in amount of the sulphydryl groups. The mechanism of inactivation of sulphydryl enzymes caused by ionizing radiation as proposed by Barron was confirmed in the case of the inactivation of urease by relatively moderate doses. (Absts. Japan. Med., 1: No. 7, 1960.)
- Research Organization:
- Kyoto Univ.
- NSA Number:
- NSA-15-022042
- OSTI ID:
- 4045617
- Journal Information:
- Journal of Biochemistry (Tokyo) (Japan), Journal Name: Journal of Biochemistry (Tokyo) (Japan) Vol. Vol: 47; ISSN JOBIA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
ACTION OF RADIATION ON ENZYMES
Inactivation of Urease by X-rays