An enzyme speeds up a cellular reaction thousands of times faster than the uncatalyzed reaction proceeds. How does the enzyme accomplish this?

Core Concept

Reactants must reach an unstable transition-state arrangement before bonds can rearrange, and the energy needed to get there limits how fast molecules convert. An enzyme binds substrates in an active site whose shape and charged groups strain specific bonds and stabilize the transition state. Lowering this barrier lets a much larger fraction of substrate molecules react at body temperature. The enzyme emerges unchanged after each cycle, so a small amount of enzyme processes enormous amounts of substrate.