What are factors that affect the activity of an enzyme-catalyzed reaction?
They are the PH , temperature, salinity and the presence of heavy metals as these are the factors that contribute to the change of the 3D shape of the protein molecule.
Enzymes are proteins having a specific 3D shape. This protein has a cavity on the side called the active site of the enzyme. It is in this area where the reaction takes place. The shape of this area is very specific and suitable to only one type reaction to take place.
If this shape changes then the enzyme will function properly and hence the whole reaction .
The factors mentioned alter the 3D shape of the whole protein and accordingly to the specificity of the shape of the active site.
The concentration of enzyme, substrate and inhibitors are also important.
Increasing the amount of the enzyme will increase the rate of reaction. Imagine you own a factory - having more workers will make work go faster, right? But once you get to a certain number of workers, you run out of jobs for them all to do, and so hiring more is simply pointless.
Having more of the substrate will also increase the rate of reaction. If you have an abundance of chores that need doing, you won't spend very long remembering the next task once one is finished. In enzymes there is much less time between releasing one substrate and getting another when the substrate is very concentrated.
Inhibitors are molecules which change the shape of the enzyme so they don't work. Having a large concentration of inhibitors in the solution means that enzymes have a high chance of being inhibited before they even begin reacting a substrate, and so inhibitors decrease the rate of reaction.