Alcohol dehydrogenase in Hordeum vulgare: changes in isoenzyme levels under hypoxia

Abstract

Alcohol dehydrogenase (ADH) activity in roots and shoots of 8-day-old barley seedlings (Hordeum vulgare cv. Sundance) rose in response to periods of flooding. The increase was accompanied by changes in the amounts and proportions of ADH isoenzymes present in the tissues. Enzyme activity in excised shoots also rose in response to enclosed atmospheres; this increase was not inhibited by actinomycin D and only partially restricted by cycloheximide. The physiological significance of the observed changes in isoenzyme proportions is discussed with reference to the kinetic properties of the isoenzymes.