Final answer:
Enzyme activity is influenced by temperature, pH, substrate concentration, and enzyme concentration. Enzymes have optimal conditions under which they function most efficiently, and deviations from these conditions can decrease enzyme activity or cause denaturation.
Step-by-step explanation:
The factors that influence enzyme activity include temperature, pH, substrate concentration, and enzyme concentration. Initially, as the substrate concentration increases, so does the rate of an enzyme-catalyzed reaction up until a point of saturation where all enzyme molecules are occupied. Temperature influences enzyme activity by increasing the rate of the reaction to an optimal point, but further increases can lead to denaturation and the loss of enzyme function. The pH affects enzyme activity because enzymes have an optimal pH range and any deviation from this range can result in decreased activity or denaturation. Enzyme concentration also affects reaction rates—the more enzyme molecules available, the higher the rate of reaction, assuming there is substrate available to bind to the enzymes.
Enzymes work most efficiently at their optimal environmental conditions, which vary among different enzymes and the organisms which produce them. For example, enzymes from thermophilic microbes are efficient at high temperatures, while enzymes from human pathogens are tuned for the body's internal temperature of approximately 37°C.
Environmental conditions such as the presence of inhibitors, coenzymes, and cofactors, as well as ionic conditions, can also regulate enzyme activity. Some of these substances may bind competitively or noncompetitively to the active site or to an allosteric site of the enzyme, thus affecting its catalytic activity.