Determination of Vm and Km

Semi-Logarithmic Plot of the Concentration versus Time After the Intravenous Injection of the Drug

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This graph represents the determination of V_max and K_m from the semi-logarithmic plot of the drug concentration versus time (intravenous injection) when elimination obeys Michaelis-Menten kinetics.

The terminal part of the curve is a straight line.  Extrapolation of this line will intersect the y-axis at a point S'.  The equation of this straight line is:

The slope is equal to

Rearranging our slope, we get

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C.3a-5