Exptl. data on the temp. relationship of alpha-amylase from Bacillus licheniformis activity published by Haq et al.(1)), were used to calc. the optimal temp., activation energy and deactivation energy of the starch hydrolysis according a resp. math. model of the reaction. The calc. values were 339.76 +/- 0.95 K, 27.16 +/- 6.89 kJ/mol, 143.54 +/- 13.31 kJ/mol, resp.