Enzyme Activity Calculator
1 U = 1 µmol product per minute
Enzyme units, activity concentration and specific activity from a measured amount of product per unit time.
Inputs
Volume of enzyme solution in the assay — gives U/mL.
Total protein in the assay — gives specific activity in U/mg.
Calculation
Activity
activity = amount of product / reaction time
Substitution
2.5 µmol / 10 min
0.25 µmol/min = 0.25 U
Inputs
- Product formed
- 2.5 µmol
- Reaction time
- 10 min
- Enzyme volume
- —
- Protein mass
- —
The enzyme unit definition used is 1 U = 1 µmol min⁻¹. Some assays define units differently — check the definition your assay uses.
This calculator assumes the measured rate is linear over the stated time. It does not fit kinetic models or estimate Km or Vmax.
About this calculator
Enzyme activity is the rate at which product is formed under the assay conditions. The unit definition used here is the common one: one unit converts one micromole of substrate per minute. Some assays define units differently, so check your assay's definition before comparing values.
Enter the enzyme solution volume to get activity per millilitre, and the protein mass to get specific activity. The calculator assumes the measured rate is linear over the stated time; it does not fit kinetic models or estimate Km or Vmax.
LabCalc is provided as a calculation aid. Users remain responsible for verifying calculations, units, chemical compatibility, experimental procedures and applicable safety requirements before laboratory use.
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