Factors Affecting Enzyme Activity

P.E.S.T. There are 4 main factors that affect Enzyme Activity. PH Level, Enzyme Concentration, Substrate Concentration, and Temperature. We already know enzymes are picky about their working condition, so anything less than perfect will mean that an enzyme could become Denatured, which means it Shrivels Up and can no longer function the way it is supposed to.

Here it is explained:

pH LEVEL

All Enzymes have an Optimum pH Level. Most Human Enzymes work best at pH Level 7, but there are exceptions such as Pepsin, which is found in the Stomach has an Optimum pH Level of 2, which is Acidic.
If the conditions are Above or Below Optimum pH, the H+ and OH- ions found in Acids and Alkalis can mess up the Ionic Bonds and Hydrogen Bonds that hold the Tertiary Structure in place. This makes the Active Site Change Shape, so the enzyme is Denatured.

ENZYME CONCENTRATION
The More Enzyme Molecules there are in a Solution, the More Likely a Substrate Molecule will Collide with it to form an Enzyme-Substrate Complex. So Increasing the Concentration of the Enzyme Increases the Rate of Reaction.
If the amount of Substrate is Limited, there comes a point where Adding Enzymes has No Further Effect on the Rate of Reaction.

SUBSTRATE CONCENTRATION
The Higher the Substrate Concentration, the Faster the Reaction due to a Lower Activation Energy. More Substrate Molecules mean that Collisions between Enzymes and Substrates is More Likely to happen, so more Active Sites will be used.
However, this is only true up to a point, this point is called the Saturation Point. After this point, there are so Many Substrate Molecules, all the Active Sites are Full, so Adding more Substrate Molecules will have No Effect on the Rate of Reaction.
Over time, the Reaction takes place, so the Substrate Concentration Decreases (unless more substrate molecules are added), so if there are no other variables, the Rate of Reaction will Decrease Over Time too. This makes the Initial Rate of Reaction the Highest Rate of Reaction.

TEMPERATURE
The Temperature Coefficient symbolised as Q10, Shows How Much the Rate of Reaction Changes when the Temperature is Raised by 10 Degrees Celcius.
At temperatures before the optimum, the Q10 Value of 2 means the Rate Doubles when the Temperature is Raised by 10 Degrees Celcius. A Q10 Value of 3 means that the Rate of Reaction Trebles.
Most Enzyme Controlled Reactions have a Q10 Value of 2.

(In the exam, you might be asked to calculate the rate of reaction. after I have finished all the content, I will write a separate post on all the horrible calculations).