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Protection by histadine against oxidative inactivation of AMP deaminase in yeast
Author(s) -
Murakami Keiko,
Onoda Yu,
Kimura Junko,
Yoshino Masataka
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700203521
Subject(s) - chemistry , biochemistry , trolox , oxidative phosphorylation , hydrogen peroxide , histidine , yeast , antioxidant , enzyme , cysteine , ascorbic acid , amp deaminase , taurine , hydroxyl radical , amino acid , adenosine deaminase , food science , dpph
Oxidative inactivation of AMP deaminase and its protection were analyzed under the in situ conditions of yeast cells. AMP deaminase was readily inactivated by an exposure to hydrogen peroxide plus copper in permeabilized yeast cells. Addition of ascorbic acid further enhanced the inactivation of the enzyme, suggesting the hydroxyl radical produced by the Fenton reaction is responsible for the inactivation of the enzyme. Addition of histidine caused an effective protection against the inactivation of AMP deaminase by hydrogen peroxide‐induced hydroxyl radical. The concentration of histidine required for half‐maximal effect was within physiological range. Cysteine showed less effective protection against oxidative inactivation. Other amino acids as potent copper‐chelating agents as well as trolox and taurine showed little or no effect. Histidine can act as a physiological “antioxidant” in yeast cells.