Why does concentration affect enzyme activity

B is a straight line representing a zero order reaction which permits accurate determination of enzyme activity for part or all of the reaction time. A represents the type of reaction that was shown in Figure 6. This reaction is zero order initially and then slows, presumably due to substrate exhaustion or product inhibition. This type of reaction is sometimes referred to as a "leading" reaction. True "potential" activity is represented by the dotted line.

Curve C represents a reaction with an initial "lag" phase. Again the dotted line represents the potentially measurable activity. Multiple determinations of product concentration enable each curve to be plotted and true activity determined. A single end point determination at E would lead to the false conclusion that all three samples had identical enzyme concentration.

PDF version of Introduction to Enzymes. Introduction to Enzymes Video. Place Order. Introduction to Enzymes The following has been excerpted from a very popular Worthington publication which was originally published in as the Manual of Clinical Enzyme Measurements. As long as there is substrate available to bind to, increasing enzyme concentration will speed up the enzymatic reaction. Once all of the substrate is bound, the reaction will no longer speed up with the increasing enzyme concentration, since there will be nothing for additional enzymes to bind to.

Enzyme is a catalytic protein which can speed up the chemical reaction without being altered in the reaction process. In the reaction process, there is no bond formed between the enzyme and the substrate, so the enzyme goes back to its original shape and can be used again.

The enzyme binds to the substrate through the active site to form an enzyme-substrate complex. They are very specific in the reaction and also to the substrate they are binding with.

When the shape of the substrate matches the active site of the enzyme, the function of the enzyme is correct, and their functioning is dependent on its three-dimensional structure.

They make the reaction easier to occur by reducing the activation energy and activating more molecules, thus carrying out the catalyst. The concentration of the enzyme is important in chemical reaction as it is needed to react with the substrate. Often a small amount of enzyme can consume a large amount of substrate. However, with the increase of enzyme concentration, the effectiveness of the active sites also increases, so these active sites will convert the substrate molecules into products.

This basically means that if the concentration of the enzyme is to be increased, there needs to be an excess of substrate, in other words, which means that the reaction must be independent of the concentration of the substrate. In order to study the effect of increasing the enzyme concentration upon the reaction rate, the substrate must be present in an excess amount; i.

Increasing Substrate Concentration increases the rate of reaction. This is because more substrate molecules will be colliding with enzyme molecules , so more product will be formed. However, after a certain concentration , any increase will have no effect on the rate of reaction, since Substrate Concentration will no longer be the limiting factor. The enzymes will effectively become saturated , and will be working at their maximum possible rate.

Increasing Enzyme Concentration will increase the rate of reaction, as more enzymes will be colliding with substrate molecules. However, this too will only have an effect up to a certain concentration , where the Enzyme Concentration is no longer the limiting factor.

This website makes use of cookies. Factors affecting Enzyme Activity The activity of an Enzyme is affected by its environmental conditions. Changing these alter the rate of reaction caused by the enzyme. In nature, organisms adjust the conditions of their enzymes to produce an Optimum rate of reaction , where necessary , or they may have enzymes which are adapted to function well in extreme conditions where they live.

Temperature Increasing temperature increases the Kinetic Energy that molecules possess. This is different for different enzymes. Most enzymes in the human body have an Optimum Temperature of around Graph showing a typical variation of enzyme activity with acidity Small changes in pH above or below the Optimum do not cause a permanent change to the enzyme, since the bonds can be reformed. Concentration Changing the Enzyme and Substrate concentrations affect the rate of reaction of an enzyme-catalysed reaction.