Questions & Answers

How does the substrate concentration affect the velocity of the enzyme reaction?

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Hint: Enzymes are chemical entities, composed of proteins, that can affect the reaction rates. Enzymes can speed up or even inhibit the reaction rate depending on their nature.

Complete answer: The rate of a chemical reaction is the measure of the velocity with which it proceeds. The molecules on which the enzyme molecules act to alter the reaction rate are called Substrates. The endpoint of this reaction is known as products. The rate or velocity of a biochemical reaction is affected by the concentrations of both enzyme molecules as well as the substrates. The effect of substrate concentration on enzyme kinetics are as follows:
The rate or velocity of the reaction increases initially with an increase in the substrate. As the reaction proceeds, at high concentrations of the substrates, the enzyme gets saturated with substrate molecules and the velocity decreases. In other words, in a condition, where the concentration of the enzyme is kept constant and there is an increase in the concentration of the substrate, there occurs an increase in the velocity or rate of the reaction. This reaches a maximum point, and after this specific point, further increases in the concentration of substrate do not cause an increase in the reaction velocity. The reason for this being, once the maximum velocity is reached, all the available enzyme molecules are converted to the enzyme-substrate complex.

Note: Multiple factors affect enzyme activity in a reaction. Some of the factors are the temperature at which the reaction takes place and the concentration of the enzyme. The enzymes can act as either promoters or inhibitors, which increase or decreases the rate of the reaction respectively.