This document summarizes several key factors that affect enzyme activity: substrate concentration, enzyme concentration, product concentration, temperature, and pH. It describes how enzyme activity increases with substrate concentration up to a point, forming a rectangular hyperbola curve. There is an optimal temperature range where activity is highest, forming a bell curve with temperature. Similarly, pH has an optimal range that produces maximum activity. The presence of inhibitors can decrease enzyme velocity. The Michaelis-Menten equation models how reaction velocity varies with changing substrate levels.