CHARACTERIZATION OF A BACTEROIDES SPECIES FROM HUMAN INTESTINE THAT DEGRADES GLYCOSAMINOGLYCANS

Polysaccharide lyases that can degrade glycosaminoglycans (GAGs) were identified in an anaerobic strain living in the human intestine. The s train was isolated from the stool of a healthy male and identified as Bacteroides sp. strain HJ-15. A detailed taxonomical study indicated t he species is a strain of Bacteroides stercoris. The isolate was cultu red and the polysaccharide lyase activity was partially purified. This enzyme preparation could act on GAGs containing either glucosamine or galactosamine suggesting the presence of both heparinases and chondro itinases. Various GAGs were incubated with the partially purified enzy me and the products formed were analyzed by strong anion-exchange high performance liquid chromatography and proton nuclear magnetic resonan ce spectroscopy. These studies demonstrated the presence of at least t wo types of polysaccharide lyases: heparin lyase and chondroitin sulfa te lyase. The eliminative mechanism of these lyase enzymes was confirm ed through the isolation of unsaturated disaccharide products. The hep arin lyase acted on both heparin and acharan sulfate, a GAG recently i solated from Achatina fulica. The Bacteroides chondroitin lyase, acted on chondroitin sulfates A, B (dermatan sulfate), and C, resembling ch ondroitin lyase ABC. The presence of a GAG-degrading organism in human intestine may pose problems for the effective oral administration of GAG drugs.