Re: How do I calculate the specific activity of trypsin?

To calculate the specific activity of an enzyme, one divides the rate (activity) under optimal 
conditions (at optimal pH, and with the substrate concentration high enough that the maximum 
rate is observed) by the protein concentration.  Your assay will give you the rate of reaction, in 
units such as micromoles per second.  Simply divide this rate by the concentration of your 
trypsin preparation.  

A new unit of enzyme activity, called the katal, has been proposed.  One katal is the amount of 
enzyme that catalyzes the conversion of one mole of substrate per second.