 Invertase

Invertase is an enzyme that hydrolyses sucrose into glucose and fructose. Its name reflects the change in optical rotation of the sugar mixture during the reaction. Optical rotation therefore provides a measurable signal of chemical conversion, provided other contributions to that signal are controlled. ^[ref]

The classic kinetic study measured initial reaction rates at different sucrose concentrations. At low substrate concentration the rate rises strongly as more substrate is supplied; at high concentration the finite amount of enzyme limits the rate. This supplies a concrete motivation for Michaelis-Menten kinetics. Product mutarotation complicates the optical readout, showing why a convenient physical signal is not automatically a direct count of reaction events.