Inhibitor

[WiNtErSuMmErAuTuM]

Does anyone know how to tell if a inhibitor is competitive or non competitive ? specifically thyroxine ??

[canalon]

Experimentally try multiple reactions with a fixed amount of enzymes and inhibitor and increasing concentration of enzymes and measure reaction rate. The results will tell you whether your inhibition is competitive or not (I let you figure out how).

[JackBean]

canalon meant constant concentration of enzyme and inhibitor and different concentrations of substrate
Anyway, you can change concentration of both inhibitor and substrate.