Proteinase catabolizes proteins by hydrolysis of peptide bonds. Proteases are inactivated by serine active-site inhibitors, such as phenylmethylsulfonyl fluoride (PMSF) and diisopropylfluorophosphate.http://www.creative-enzymes.com/product/Native-Bacillus-Licheniformis-Alkaline-Protease_939.html