Which of the following statements regarding simple michaelis- menten enzyme kinetics are correct? a) the maximal velocity vmax is related to the maximal number of substrate molecules b) km is expressed in terms of a reaction velocity (e. g.mol s) c) km is the dissociation constant of the enzyme-substrate complex d) kym is the concentration of substrate required to achieve half of vmax e) km is the concentration of substrate required to convert half the total enzyme into the enzyme- substrate complex select one: a. a, b and c b. a and d c. c, d and e d. e only e. a only