The preparation and properties of crystalline alcohol dehydrogenase from liver.

Kinetic studies of alcohol dehydrogenase prepared from horse liver by different methods have given different results (Theorell, Nygaard & Bonnichsen, 1955; Dalziel, 1958; Theorell, 1958; K. Dalziel, unpublished work, 1957). The most active crystalline preparations have been obtained by a modification of earlier methods (Bonnichsen, 1950; Bonnichsen & Brink, 1955) in which the principal new feature was chromatography of the crude enzyme preparations on carboxymethylcellulose before crystallization (Dalziel, 1958). Such products were homogeneous in the ultracentrifuge (Ehrenberg & Dalziel, 1958), but electrophoresis indicated the presence of small proportions of a second active component, and it was suggested that this may be formed from the major component during agitation of the liver extract with ethanol and chloroform to denature haemoglobin (Tsuchihashi, 1923; Bonnichsen, 1950). It has now been found that this step can be omitted, and haemoglobin removed instead by modification of the ammonium sulphate fractionation and chromatography. Some properties of the crystalline product are described, and kinetic data are briefly considered with reference to earlier work.