Zinc release from irradiated yeast alcohol dehydrogenase.
The release of Zn2+ from gamma-irradiated yeast alcohol dehydrogenase has been measured using atomic absorption spectrometry. Radiolysis is accompanied by release of Zn2+ at a rate which is dependent on the nature of the free radicals available for reaction. Hydroxyl radicals and hydrogen atoms readily cause zinc release with G values of 0.13 and 0.11 (/100 eV) respectively, whereas hydrated electrons are considered not to contribute to the demetallization process. The radiolytically generated radical anions I2-., (SCN)2-. and Br2-. enhance the rate of zinc release. Evidence is presented that the enzyme is demetallized as a result of free radical reactions at cysteine and histidine residues.
D000426:Alcohol Dehydrogenase / Q000528:radiation effects*; D003037:Cobalt Radioisotopes; D005720:Gamma Rays; D013054:Spectrophotometry, Atomic; D015032:Zinc
D003037:Cobalt Radioisotopes; D000426:Alcohol Dehydrogenase; D015032:Zinc