The efficacy of an enzyme for a chemical reaction is typical

The efficacy of an enzyme for a chemical reaction is typically expressed in terms of the
enzyme kinetics. The three primary parameters for enzyme kinetics are the turnover number, the
maximal velocity, and the Michaelis-constant. Describe what each of these parameters represent
and how they express or describe the activity of an enzyme.

Solution

Turnover number (k_cat) is defined as the maximum number of chemical conversion of substrate molecules into product under saturating conditions per unit time per unit quantity of enzyme.

K_cat = V_max/ E_total                                                     [Where K_cat= turn over number

                                                            V_max = Maximun reaction rate                                                                                                                                    E_total= Total enzyme]

Michaelis constant

K_M

: It is the substrate concentration at which reaction rate is half of V_max. Low K_M means less substrate requirement for saturating enzyme and to attain maximum velocity. And more K_M means more substrate concentration to attain maximum velocity. Therefore Km is nothing but the substrate concentration required to attain Vmax.

Michaelis–Menten\' kinetics is one of the best-known models of enzyme kinetics. when substrate S binds reversibly to an enzyme E to form an enzyme-substrate complex ES, which reacts irreversibly to generate a product P and to regenerate the free enzyme E. The reaction shown as follows:

E + S<------> E-S ----->E + P

[E=enzyme, S=substrate, P= product, E-S=E-S complex]

The Michaelis-Menten equation for above reaction:

V= Vmax [S]/K_m+[S]