How do you determine Vmax in enzyme kinetics?

Answer 1

Vmax is the maxim initial velocity (Vo) that an enzyme can achieve. Initial velocity is defined as the catalytic rate when substrate concentration is high, enough to saturate the enzyme, and the product concentration is low enough to neglect the rate of the reverse reaction. Therefore, the Vmax is the maximum catalytic rate that can be achieved by a particular enzyme.

Km is determined as the substrate concentration at which 1/2 Vmax is achieved. This kinetic parameter therefore importantly defines the affinity of the substrate for the enzyme.

These two parameters for a specific enzyme defines:

Vmax - the rate at which a substrate will be converted to product once bound to the enzyme.

Km - how effectively the enzyme would bind he substrate, hence affinity.

Answer 2

This would have to be done via experiments. One would use a spectrophotometer, and record the rate at different substrate concentrations. The point at which the rate seems to no longer increase would be the Vmax. This relates to Michaelis-Menten equation of v=Vmax[S]/km+[S]

Answer 3

Vmax in enzyme kinetics is determined by plotting the initial reaction rates against substrate concentration, and then extrapolating the curve to the point where it theoretically intersects with the y-axis. This point represents the maximum reaction rate that the enzyme can achieve when all enzyme active sites are saturated with substrate.