| Literature DB >> 7957879 |
K Hitschke1, R Bühler, H J Apell, G Stark.
Abstract
Free radicals produced by water radiolysis were used to study the inactivation of the enzymatic activity of the Na,K-ATPase. A decrease of the activity to virtually zero with a mono-exponential dependence on the radiation dose was observed. The inactivation process is initiated by hydroxyl radicals. This was shown by the effect of appropriate radical scavengers such as t-butanol, formate and vitamin C. In all cases a significant increase in the characteristic D37 dose of inactivation was observed. Inactivation was found to show a so-called inverse dose-rate effect, i.e., the sensitivity of the enzyme to radical attack is increased if the dose rate is reduced. The data were found to agree with the relationship 1/D37 approximately 1/D1/2, which is known to be a strong indicator of a radical chain mechanism. This means that the inactivation, after initiation by single radicals, is amplified by a subsequent chain mechanism.Entities:
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Year: 1994 PMID： 7957879 DOI： 10.1016/0014-5793(94)01067-6
Source DB: PubMed Journal: FEBS Lett ISSN： 0014-5793 Impact factor: 4.124