DEGRADATION OF COLLAGENOUS SUBSTRATES BY BACTEROIDES MELANINOGENICUS

Abstract

An oral strain of Bacteroides melaninogenicus has been shown to possess an enzyme capable of hydrolyzing native collagen. Gelatin, azocoll, casein, egg albumin, and plasma proteins are also attacked by the bacterium. The collagenolytic enzyme is intimately associated with the cell, but is released during cell autolysis. Quantitative studies were undertaken using soluble collagen as substrate and it was shown that the enzyme functions optimally over a range of pH 6.8 to pH 7.3, and is heat-labile. Calcium ions exerted a slight stimulatory effect on dialyzed enzyme preparations, and overcame ethylenediaminetetraacetic acid inhibition. L-Cysteine hydrochloride activated dialyzed enzyme preparations and also partially reversed inhibition caused by mercuric chloride. A total of 30 strains of B. melaninogenicus from the oral cavity and intestinal tract of man and from the rumen of cattle were tested for activity against reconstituted collagen extracted from guinea pig skins. All 30 strains possessed collagenolytic activity against this substrate.