How do I convert the concentration (mg/mL) of Dispase II I currently use into FITC-BSA Units/mL?

The Dispase II product is a much cruder preparation of neutral protease than our BP protease, but both originate from Paenibacillus polymyxa fermentations . The FITC-BSA specific activity of the Dispase II product is less than 10% that of our BP Protease and can vary dramatically between lots. To substitute BP Protease for Dispase II, a good rule of thumb is to replace Dispase II targeted at 1.0 mg/mL with 5,000 FITC-BSA Units/mL (roughly 30 µg/mL BP Protease).