Immunological reactivity of native and modified alcohol dehydrogenase (ADH)

The extent to which treatment of horse liver alcohol dehydrogenase (ADH) by procedures known to disturb the Zn association induced conformation changes detectable by immunological techniques has been investigated. Treatment of ADH by sodium dodecyl sulphate or by total reduction and carboxymethylation leads to complete loss of reactivity with a rabbit immune serum against the native enzyme. After selective carboxymethylation the enzymatic activity was reduced but the preparation had the same immunological activity of the native enzyme. Similar results were obtained when ADH was treated with reagents known to react with the "functional" Zn atoms, such as sodium dietyldithiocarbamate, 1,10 phenanthroline, and 2,2' bipyridine. In contrast dialysis in 0.01M phosphate buffer containing 0.1mM EDTA removing the "structural" Zn atoms leads to a parallel decrease of enzymatic and immunological activity. Thus loss of "structural" Zn atoms affects the immune reactivity of ADH differently from the loss of "functional" Zn atoms.