EFFECT OF INHIBITORY EXTRACTS OF ENDOPHYTES ASPERGILLUS FISCHERI VO1R AND FUSARIUM SP.-AL142R ON THE KINETIC CHARACTERISTICS OF PANCREATIC LIPASE

This article presents the results of studying the effect of extracts of endophytic fungi Aspergillus fischeri VO1R, isolated from the root of Viola odorata and Fusarium sp.-AL142R, isolated from the root of Allium longicuspis Regel, on the kinetic characteristics of pancreatic lipase. The extracts of these endophytes have the ability to suppress pancreatic lipase activity by 91.5% and 88.5%, respectively, with IC50 values of 20.5 and 20.7 µg/mL, which is comparable to the IC50 of the xenical standard (20.6 µg/mL). The A.fischeri VO1R extract was shown to reduce the maximum reaction rate (Vmax) by 4-fold to 0.005 mg/min compared to 0.02 mg/min without inhibitor. Meanwhile, the Km value both in the presence and absence of the inhibitor remains unchanged at 10 mg/mL. These data indicate a non-competitive mechanism of action of the inhibitor extract of A.fischeri VO1R, since it does not reduce the affinity of lipase for the substrate. In the presence of the inhibitor extract of Fusarium sp.-AL142R, as well as Xenical, the value of Km (16 mg/ml) increases 1.5-fold, Xenical under experimental conditions increases Km almost 2.5-fold (25.0 mg/ml), while Vmax remains at the control level. The data obtained allow us to conclude that the inhibitor compounds of the endophyte A.fischeri VO1R act non-competitively, whereas lipase inhibitors from Fusarium sp.-AL142R and Xenical exhibit a competitive type of inhibition.