Enzyme specifity is given by
In a series of test tubes, equal volume of enzyme solution is taken, bt increasing quantity of substrate is added and the rate of reaction is assayed in each tube.The velocity(V) is expressed in macromolecules of substrate conveed per minute.if the velocity is plotted against the substrate conc. a typical curve is seen. as substrate conc. is increased, the velocity is also correspondingly increased in the initial phases, but the curve flattens afterwords.the specificity constant also called kinetic efficiency is a measure of how efficiently an enzyme conves substrates into products. A comparison of specificity constants can also be used as a measure of the preference of an enzyme for different substrates (i.e., substrate specificity). The higher the specificity constant, the more the enzyme "prefers" that substrateThe following equation, known as the Michaelis-Menten model, is used to describe the kinetics of enzymes:E + S = k r k f ES - k c a t E + P where E, S, ES, and P represent enzyme, substrate, enzyme-substrate complex, and product, respectivelyThe Michaelis constant, in turn, is defined as follows:The Michaelis constant is equal to the substrate concentration at which the enzyme conves substrates into products at half its maximal rate and hence is related to the affinity of the substrate for the enzyme. The catalytic constant is the rate of product formation when the enzyme is saturated with the substrate and therefore reflects the enzyme&;s maximum rate. The rate of product formation is dependent on both how well the enzyme binds the substrate and how fast the enzyme conves substrate into product once the substrate is bound. For a kinetically perfect enzyme, every encounter between enzyme and substrate leads to product and hence the reaction velocity is only limited by the rate the enzyme encounters substrate in solution. Ref: DM Vasudevan, page no: 56
Km
Vmax
Both
None
Enzymes