List the main factors that alter the speed of enzymatic reactions.

There are five main factors which affect the rate of
enzyme-mediated reactions.

1) Enzyme concentration. Adding
enzyme molecules will speed up the reaction, until a saturation point is
reached.

2) Substrate concentration. Assuming sufficient
enzyme concentration, adding substrate molecules will increase the rate, again until
saturation is reached.

3) Temperature. Reactions occur
faster at warmer temperatures because the rate of collisions between molecules
increases. However, if the temperature gets too hot the enzyme may denature and fail to
function. All enzymes have an optimal temperature range determined by these two
factors.

4) pH level. Enzymes also have an optimal pH
level; if the environmental pH is too high or too low, the fold structure of the enzyme
may be affected, causing the molecule to change shape and lose
functionality.

5) Concentration of salts in the medium.
Again, there is an optimal range, outside which the enzyme molecules may
denature.