Catalase was isolated from the Saccharomyces cerevisiae yeast and studied for activity at 35-50 degrees C by using an O-2 electrode. The pre-exponential factor of thermal deactivation and the activation energy were detd. Statistical coeffs. showed a compliance of exptl. and computational data and thus confirmed the proposed math. model. The half-life times of the Saccharomyces cerevisiae catalase at pH 7.0 and 35 degrees C or 50 degrees C were 4.67 h or 0.35 h, resp.