As mentioned above, enzymes are proteins in nature and are extremely sensitive to thermal changes which trigger their reactions. Enzymes have a range of temperature(between 37 to 40C°) at which it is more active(Optimal temperature). At optimal temperature, enzymes are more active and gradually decrease as the temperature moves out of the optimal point. When the temperature gets too high or too low, the enzyme activities stop completely due to a change in its natural composition and state

Nice points there concerning enzyme activity. I want to add that when the temperature is too low, the enzyme is in active due to the water crystals at the active site of the enzyme and when the temperature is too high the enzyme denatures because of the destruction of the amino acids present at the active site.

Same principle holds for pH

Some enzymes need certain inorganic metallic cations and anions for optimum activity. Some metallic cation are Mg2+, Mn2+, Zn2+, Ca2+, Co2+ etc and anions (chloride ion (CI–))

Some of these activators are called cofactors. Some examples include NAD⁺and NADH+H⁺, FAD⁺, AND FADH+H⁺used as cofactors in glycolysis and the electron transport chain.

Beautiful post there I invite you to go through my post, which is on Staining Methods as Diagnostic Tools