Give the MichaelisMenten equation and define each term in it

Give the Michaelis-Menten equation and define each term in it. Does this equation apply to all enzymes? If not, to which kind does it not apply? What is a zymogen (proenzyme)? Explain briefly with an example. An enzyme catalyzes a reaction at a velocity of 20 mu mol/min when the concentration of substrate (S) is 0.01 M. The K_m for this substrate is 1 times 10^-5 M. Assuming that Michaelis-Menten kinetics are followed, what will the reaction velocity be when the concentration of S is (a) 1 times 10^-5 M and (b) 1 times 10^-6 M? Explain how a biochemist might discover that a certain enzyme is allosterically regulated. What are competitive, uncompetitive and non-competitive inhibitors? Illustrate the differences using the Line- double reciprocal plots for enzymes in the presence of competitive, uncompetitive and non-competitive

Solution

Ans 4. Michaelis menten equation ia given as

V_o = V_max([S] / [S] + K_m)

Where V_o is the initial velocity of the reaction

V_max is maximal rate of equation

[S] is concentration of substrate

And k_m ia Michaelis menten constant.

This equation does not apply to allosteric enzymes as they have more than two subunits and active sites . They observe a sigmoidal kinetics instead of Michaelis menten kinetics.

Also This equation does not hold good for most of the enzymes present in the cell. Because most of these enzymes act on reactions that are at equilibrium and they are unsuitable for most of the other enzymes present within a cell.