[Dissociation of Penicillium vitale catalase under the effect of urea and acid pH].

Conditions are studied for Penicillium vitale catalase dissociation into subunits under the effect of urea (0.7-8.5 M) and acid pH (5.0-2.0). In 8.0 M urea (pH 5.0) a molecule of the P. vitale catalase dissociates with formation of the components, the sedimentation coefficient of which is 2.4+/-0.2S, the molecular weight is 153000+/-2800. Dissociation at pH 2.2 in 4.0 M urea results in formation of components with the sedimentation coefficient 2.2+/-0.3 S. The catalase molecule dissociation under the mentioned conditions is accompanied by a loss in the enzyme activity. The results obtained show that dissociation of the P. vitale catalase molecule requires more rigid conditions than dissociation of the animal catalase. At the same time the catalase after dissociation in 8.0-8.5 M urea loses its ability to reassociation with a decrease in the urea concentration up to 0.08 M.