Write down an equation for the rate of a reaction catalyzed by a mixture of two enzymes, each of which obeys Michaelis–Menten kinetics, one with limiting rate V1 and Michaelis constant Km1 and the...

Write down an equation for the rate of a reaction catalyzed by a mixture of two enzymes, each of which obeys Michaelis–Menten kinetics, one with limiting rate V1 and Michaelis constant Km1 and the other with V2 and Km2 . Differentiate this equation twice with respect to a and show that the resulting second derivative is negative at all values of a. What does this imply about the shape of a plot of v against a?