Chemistry
Enzyme Activity Calculator
Convert a rate of product formation into enzyme units and specific activity.
Your inputs
Change any value to update the result instantly.
Enzyme activity
1.2 U
Specific activity
2.4 U/mg
Volumetric activity
1.2 U/mL
In katal
0 kat
Definition used
One unit (U) converts one micromole of substrate per minute under the assay conditions
Activity only means something alongside the assay conditions: temperature, pH, substrate concentration and buffer. Specific activity rises as the enzyme is purified.
What this calculator does
Converts product formed per unit time into enzyme units, specific activity and katal.
What your result means
One unit converts one micromole of substrate per minute under the assay conditions.
Formula and working
Activity = Δn_product / Δt; specific activity = activity / mass of enzyme
- 1
Collect the inputs
Product formed = 12 µmol; Reaction time = 10 min; Enzyme protein used = 0.5 mg; Assay volume = 1 mL
- 2
Apply the formula
Activity = Δn_product / Δt; specific activity = activity / mass of enzyme
- 3
Result
Enzyme activity = 1.2 U
Frequently asked questions
Symbols and assumptions
- U
- Enzyme unit, µmol/min
- kat
- Katal, mol/s
- specific activity
- Units per mg of protein
- • Initial-rate conditions with substrate in excess.
- • Product measurement is accurate over the timed interval.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • Activity is meaningless without stating temperature, pH, buffer and substrate concentration.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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