Figure 3. (+)-Rutamarin is a PTP1B inhibitor.

(a) Rut inhibits the purified PTP1B enzyme activity with IC₅₀ value of 6.4 µM. (b) The double-reciprocal plots indicates that Rut is a competitive inhibitor of PTP1B determined by Lineweaver-Burk method. (c) Rut (20 µM) enhances the insulin but not the pervanadate (100 µM)-induced GLUT4 translocation in CHO/GLUT4 cells. Data are presented as means ± s.e.m (*P<0.05, **P<0.01) from three independent experiments.