The factors that influence enzyme activity include temperature, pH, enzyme concentration, and substrate concentration. Each enzyme has an optimal temperature and pH at which it functions most effectively. Deviations from these optimal conditions can lead to decreased catalytic efficiency or denaturation of the enzyme. Additionally, the presence of inhibitors or activators can modulate enzyme activity, affecting metabolic pathways. Understanding these factors is vital for applications in biotechnology and medicine, particularly in developing enzyme-based therapies.