The Oxidation of Yeast Alcohol Dehydrogenase-I by Hydrogen Peroxide in vitro

摘要

Oxidative damage to the sulfur-containing amino acids, cysteine and methionine, is a major concern in biological studies. Yeast alcohol dehydrogenase-I (YADH-1), which is a zinc-containing protein present in baker's yeast, contains eight cysteines and six methionines in its primary sequence. YADH-1 accounts for the major ADH activity in yeast cells. Previous studies indicated that inactivation of this enzyme upon oxidation was correlated with zinc release and thiol/thiolate oxidation. So far, the identities and structures of the resulting oxidized products are still uncertain. Here, we report that Cys43, one of two cysteines in the active site of YADH-1, is more sensitive to H2O2 treatment than other cysteines in YADH-1. This work provides new insights into YADH-1 activity under oxidizing conditions.