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Enzymes are a type of protein that are natural catalysts. Catalysts are molecules that increase the rate of reaction between two other molecules without being altered themselves.
Enzyme function...
An enzyme functions by allowing for one of the substrates involved in a reaction to bond with the active site of an enzyme, thus reducing weakening the rest of the substrate's bonds and lowering the activation energy required for the second substrate to react with the first.
Enzyme - Substrate specificity...
Different enzymes can only bond with to different, specific sets of substrates, this is known as enzyme-substrate specificity. The form of an enzyme is such that it can only bond with the substrate. The enzyme can, however, mold around a substrate somewhat. Much like a glove stretches and molds around a hand, so can an enzyme.
Factors Effecting the Efficiency of Enzymes...
pH...
As enzymes are proteins, if the pH of it's environment is too low or too high, they will begin to denature, thus losing effectiveness
Temperature...
Similarly to pH, if the temperature in the environment of an enzyme is too high, it will begin to denature. However, low temperatures do not denature the enzyme, only reduce the number and strength of collisions in the substance, and thus the likelihood of a collision with enough kinetic energy to match the activation energy of the reaction.
Substrate concentration...
Simply put, a higher substrate concentration means a greater chance there is a substrate in each enzyme, however, given a high enough concentration, all enzymes in the solution will be occupied, thus further increase in concentration would have no effect.
Enzyme Inhibition...
Enzyme inhibition refers to when an molecule (inhibitor) interacts with an enzyme in order to stall it's function.
Competitive inhibition...
Competitive inhibitors are molecules that have the right form and charge to bond with the active site of an enzyme, however, do not react with the substrate, thus blocking the correct substrate from bonding with the active site. If the substrate concentration increases in the environment of the enzyme however, the inhibitor will be expelled from the active site, and enzyme function will resume as normal.
Non-competitive inhibition...
Non-competitive inhibitors work by bonding to another part of the enzyme, not the active site, and altering the enzyme's form by breaking it's bonds, thus stopping it from working. Unlike competitive inhibitors, this process is not reversable.
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