biologia plantarum

Biologia plantarum 13:33-42, 1971 | DOI: 10.1007/BF02930744

On plant alcohol dehydrogenases

Sylva Leblová¹, Ilona Zimáková¹, Jana Barthová¹, Dana Ehlichová¹

¹ Department of Biochemistry, Natural Science Faculty, Charles University, Praha

We have found in a number of plants (lentil, lupine, bean, barley, oats, rye, wheat, cucumber, melon, flax, sunflower and rape) that varying amounts of ethanol are formed under natural anaerobiosis and, that in later growth periods these plants continue to react to anaerobiosis by formation of ethanol. When the testa has opened in germinating plants or, when plants are transferred from the anaerobic atmosphere to air, ethanol disappears.
Plants contain alcohol dehydrogenases, the activity of which depends on the alcohol concentration in their tissue; the maximum concentration is reached during natural anaerobiosis, rising in the course of further growth when the plants are kept in a nitrogen atmosphere.
Alcohol dehydrogenases of the plants studied are localised in the soluble cell fraction notsedimenting at 120 000 g, their pH optimum is in the weakly alkaline region and their Michaelis constants are equal in order of magnitude (10^-5m). They are all inhibited in the same way by Zn²⁺, Cu²⁺, Hg²⁺, B₄O₇^2- ions, p-chloromercuric benzoate, iodoacetate, EDTA and phenantroline, which may be considered as evidence of the presence of -SH groups. The specific activity of alcohol dehydrogenase preparations is higher in plants grown in light than in plants grown in the dark.
The specific activity of plant alcohol dehydrogenases can be increased by precipitation with ammonium sulphate by at most one order of magnitude, while all the activity is lost by this purification process in the case of cereals.
The following isoenzyme composition of ADH was found by means of electrophoresis on polyacrylamide: the enzyme from poas and sunflower, for example, is composed of three, that from wheat and oats six, the enzyme from maize and barley of five isoenzymes.

Received: February 25, 1970; Published: January 1, 1971  Show citation