why the increasing in substrate concentration increase in the rate of reaction of enzymes.
The increase in substrate concentration generally leads to an increase in the rate of enzyme-catalyzed reactions. This phenomenon is known as substrate concentration or substrate level effect.
To understand why this happens, we need to consider the mechanism of enzymatic reactions. Enzymes are proteins that act as catalysts, meaning they speed up the rate of chemical reactions without being consumed themselves. Enzymes achieve this by binding to a specific molecule called a substrate and converting it into a product.
Enzymes have active sites, which are specific regions where the substrate binds. The binding of the substrate and enzyme is often described using the "lock and key" or "induced fit" models. In the lock and key model, the substrate fits perfectly into the active site of the enzyme. In the induced fit model, the active site of the enzyme undergoes conformational changes upon substrate binding.
When the substrate concentration is low, there is a limited amount of substrate available to bind with the enzyme. As a result, the enzyme may not be fully utilized, and the rate of the reaction may be relatively slow.
However, as the substrate concentration increases, more substrate molecules are available to bind to the enzyme. This increases the likelihood of collisions between the substrate and enzyme, leading to more frequent formation of enzyme-substrate complexes. As a result, the rate of the reaction increases due to an increase in the number of enzyme-substrate complexes formed and, subsequently, the rate of product formation.
It's important to note that there is a point at which the rate of reaction reaches a maximum and does not increase further with an increase in substrate concentration. This is known as the saturation point. At this point, all the active sites of the enzyme are occupied by substrate molecules, and adding more substrate does not have any additional effect on the reaction rate.
To summarize, the increase in substrate concentration leads to an increase in the rate of enzyme-catalyzed reactions because a higher substrate concentration results in more frequent formation of enzyme-substrate complexes and, consequently, an increased rate of product formation.