| Autor: |
Patek, David R., Hellerman, Leslie |
| Zdroj: |
Journal of Biological Chemistry; April 1974, Vol. 249 Issue: 8 p2373-2380, 8p |
| Abstrakt: |
As an approach to the investigation of inhibiting effects of substituted hydrazines with monoamine oxidases, highly active bovine kidney mitochondrial oxidase was used to study the mechanism of phenylhydrazine-induced inactivation. Treatment of the enzyme under N2with a 3-fold excess of inhibitor produced almost complete reduction of the enzyme flavin. Introduction of oxygen then caused 80% reoxidation of reduced flavin with equivalent restoration of enzyme activity. With oxygen present initially phenylhydrazine effected almost complete irreversible inhibition. It appears that the enzyme catalyzed the oxidation of phenylhydrazine producing a highly unstable product, phenyldiazene (phenyldiimide), which inactivated the enzyme irreversibly. Such an inactivation was observed with phenyldiazene itself, prepared in situvia the decarboxylation of phenylazoformate. Our evidence, including a Hammett study correlating the effects of nuclear substitution in phenylhydrazines with rates of hydrazine-induced inhibition (ρ = -1.9) suggests that initial phenylhydrazine reduction of the flavoenzyme is rate-determining in the over-all (aerobic) inhibition process. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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