Characteristics of the extracellular lipases from Corynebacterium acnes and Staphylococcus epidermidis

Abstract

The lipases (glycerol ester hydrolases, 3.1.1.3) from two cutaneous bacteria Corynebacterium acnes (Propionibacterium acnes, Group II) and Staphylococcus epidermidis were partially purified and characterized to permit the screening of possible enzyme inhibitors. Ultimately one of these inhibitors may be useful in the topical treatment of acne vulgaris. Although these enzymes are similar in function, they are distinctive in their characteristics. The enzymes were partially purified from liquid culture broth by either ultrafiltration or precipitation followed by gel filtration on Sephadex G 100 and chromatography with a cellulose ion exchanger. These enzyme preparations demonstrated their greatest catalytic activity against emulsions of tributyrin > triolein > tricaprylin > trilaurin > tristearin. The patterns of triglyceride hydrolysis by the two lipases, however, were different. The enzyme from S. epidermidis behaved similarly to pancreatic lipase and cleaved the α positions of the triglycerides more rapidly than the β position, producing monoglyceride intermediates. The C. acnes lipase cleaved both positions with equal facility, producing only glycerol and free fatty acids. C. acnes lipase was stable in the acidic pH range between 5-8; while the S. epidermidis lipase was inactivated in that range and stable between pH 7-10. C. acnes lipase was generally more sensitive to enzyme inhibitors and was very effectively inhibited by diisopropylfluorophosphate (DFP) and some of its analogs. S. epidermidis lipase was not inhibited by DFP although some of the DFP analogs were effective inhibitors. The lipase activity present within comedones removed from acne patients was inhibited 70% by DFP (0.1 mM), suggesting that the major lipase in comedones originates from C. acnes.