The units of enzyme preparations are core indicators for measuring enzyme activity (catalytic capacity), not mass/weight units. Due to different national standards, these units vary across countries. Currently, the main internationally recognized standard units are IU, U, and Kat (katal). However, in industrial enzymes, certain standardization has been formed based on differences in enzyme substrates and application scenarios.
Below is a table of common units for industrial enzymes:
|
Unit |
Applicable Enzymes |
Definition (Industry Standard) |
Main Using Regions/Industries |
|
DU (Dextrinizing Unit) |
α-Amylase |
The amount of enzyme required to catalyze 10g of starch into dextrin within 1 hour |
Global food processing (baking, starch sugar) and feed industries |
|
PU (Protease Unit) |
Neutral Protease/Alkaline Protease |
The amount of enzyme required to hydrolyze casein to produce 1μg of tyrosine within 1 minute at 37℃ and pH 7.5 |
Detergent, leather tanning, and feed industries (commonly used in European, American, and Southeast Asian markets) |
|
FIP (Fibrinolytic Unit) |
Thrombolytic Enzymes (e.g., Nattokinase) |
Activity unit for fibrin dissolution under specific conditions |
Pharmaceutical and health product industries (preferred in Japan and the EU) |
|
BGU (β-Glucanase Unit) |
β-Glucanase |
The amount of enzyme required to decompose β-glucan to produce 1μmol of glucose within 1 minute at 50℃ and pH 5.0 |
Beer brewing and feed industries (commonly used in German and Belgian breweries) |
|
LipU (Lipase Unit) |
Lipase |
The amount of enzyme required to hydrolyze olive oil to produce 1μmol of fatty acid within 1 minute at 37℃ and pH 7.0 |
Food processing and detergent industries (globally used; reaction conditions need to be verified in detail) |
Enzyme preparation units are closely related to enzyme activity. For the same enzyme unit, higher enzyme activity means higher product content and a correspondingly higher price. Prices can also differ several times between different enzyme activity units. For example, there is a significant price gap between thrombolytic enzymes with 200FIP/g and 200FIP/mg. Therefore, when purchasing enzyme products, remember to pay attention to the units of the enzyme preparation.