Enzyme Activity Calculator

Enzyme activity is the catalytic efficiency of an enzyme, measuring the rate at which it converts substrate into product. One unit (U) of enzyme activity is defined as the amount of enzyme that converts 1 μmol of substrate per minute under specified conditions.

To calculate enzyme mass needed, use the formula: Mass = (Desired Activity × Final Volume) / Stock Activity. Enter your desired activity in U/mL, final buffer volume, and stock enzyme activity in U/mg to get the required mass.

Specific activity is the enzyme activity per unit mass of protein, expressed in units per milligram (U/mg). It indicates enzyme purity and catalytic efficiency - higher specific activity means more pure or active enzyme preparation.

Measuring enzyme activity is crucial for quality control, determining enzyme concentration for experiments, comparing different enzyme preparations, and ensuring reproducible results in biochemical assays and industrial processes.

Use the Beer-Lambert law: first calculate concentration change (mM/min) = ΔA/min ÷ (ε × path length), then multiply by reaction volume and dilution factor to get enzyme activity in μmol/min (units).

Total activity is the absolute amount of enzyme activity in units (U), while specific activity is activity per unit mass (U/mg). Specific activity indicates enzyme purity, while total activity shows the absolute catalytic capacity.

Key factors include temperature, pH, substrate concentration, enzyme concentration, buffer composition, and assay conditions. Standardized conditions are essential for accurate and reproducible measurements.

Calculate the required enzyme mass using the desired final activity and volume. Dissolve the calculated mass in your buffer to achieve the target activity concentration. Always verify by measuring actual activity.