698 tools
All

Enzyme Activity Calculator

Convert a molar rate and assay volume into enzyme units (µmol/min) and katals.

 

 

Activity (U)
Activity (kat)

About this calculator

Use this calculator after an enzyme assay when the slope is a concentration change and you need U and katal for the report.

Enter the rate as mol/(L·min) in the assay mix. Activity in U = rate × 10⁶ × volume in litres (so µmol/min in that volume). Katal = (rate / 60) × volume, which is mol/s in that volume. Assay volume can be entered in litres (L) or gallons (gal); the calculator converts to litres. A 1 mL cuvette is 0.001 L. One U is 16.67 nkat.

Rate (mol/L·min): Reaction rate as a change in molarity per minute, for example 1.2e-8 from the slope.

Assay volume: Assay volume in L or gal.

Activity (U): Enzyme units, µmol of substrate per minute in the assay volume.

Activity (kat): Activity in katals (mol/s).