Detailed analysis of new, mathematical model of enzymatic, 1,3-specific triacylglycerols alcoholysis catalyzed by lipases was discussed based on experimental data of tricaprylin isopropanolysis. Irreversibility of acyl bounds cleavage in glycerides, reversible monoglycerides isomerization and irreversible enzyme deactivation has been assumed. A good agreement between the model and experimental data has been obtained.