As the temperature increases the molecules moves faster due to increased kinetic energy of molecules. In an enzyme catalysed reaction this elevation in temperature and kinetic energy of molecules, results in the increased enzyme and substrate collision. And hence the rate at which the product is formed increases. But if the temperature is too high the enzyme will be denatured.
2. Enzyme concentration.
An increase in enzyme concentration will increase enzyme-substrate collision (speed up the rate of reaction) until the saturation point is reached.
3. Substrate concentration.
Depending on the whether there is sufficient enzyme concentration in the solution, an increase in substrate concentration will speed up the reaction rate until the saturation point is reached.
According to dictionary.com, saturation point is the point at which a substance will receive no more of another substance in solution, chemical combination, etc.
4. Ph level
All enzymes have an optimum Ph level at which they operate best. If the Ph of the solution (enzyme and substrate) is lower than the optimum Ph the enzyme may be rendered inactive, whereas at a high Ph the enzyme denatures.