Sequential degradation of keratan sulfate by bacterial enzymes and purification of a sulfatase in the enzymatic system.

Pseudomonas sp. IFO-13309 and Actinobacillus sp. IFO-13310, bacteria which exhibit a symbiotic growth in a medium containing keratin sulfate as a sole carbon source, were isolated from soil. Extracts of these organisms were shown to contain an endoglycosidase, a sulfatase, and exo-beta-D-galactosidase, and an exo-beta-D-N-acetylglucosaminidase which, together, catalyze an extensive cleavage of corneal keratan sulfate. The Pseudomonas extract was particularly rich in the endoglycosidase activity and poor in the exoglycosidase activities. The Actinobacillus extract, in sharp contrast, contained principally the exoglycosidases. The sulfatase activity did not show this marked difference in distribution. A sulfatase was purified from the crude extract of Actinobacillus. The purified sulfatase reacted little or not at all with keratan sulfate, but acted on 2-acetamido-2-deoxy-6-O-sulfo-D-glucose, 2-acetamido-2-deoxy-6-O-sulfo-beta-D-glucosyl-(1 leads to 3)-D-galactose, and a tetrasaccharide trisulfate having 2-acetamido-2-deoxy-6-O-sulfo-D-glucose at the nonreducing end (prepared from keratan sulfate with an endogalactosidase). The enzyme removed one sulfate group from the tetrasaccharide trisulfate, producing an oligosaccharide which, unlike the parent oligosaccharide, was susceptible to hydrolysis with exo-beta-D-N-acetylglucosaminidase. The data suggest that the nonreducing end is the only site at wich enzymatic desulfation is carried out.