The enzyme "chondroitinase-ABC" has been purified from Proteus vulgaris, NCTC 4636, which was adapted on a medium containing chondroitin sulfate C. It degrades chondroitin sulfates A, B, and C more efficiently than chondroitin and hyaluronic acid at pH 8. It catalyzes an elimination reaction, yielding Δ4,5-unsaturated disaccharides. It is accompanied by two sulfatases, chondro-4-sulfatase and chondro-6-sulfatase, which are required for the hydrolytic desulfation of chondroitinase products. Chondro-4-sulfatase converts Δ4,5-unsaturated disaccharide 4-sulfate to nonsulfated disaccharides, while chondro-6-sulfatase desulfates Δ6-sulfated disaccharides. Another chondroitinase, "chondroitinase-AC," has been purified from Flavobacterium heparinum, ATCC 13125, and shares similar properties with chondroitinase-ABC. It does not act on chondroitin sulfate B. Both enzymes degrade chondroitin sulfates A, B, and C via an elimination mechanism, producing Δ4,5-unsaturated disaccharides. The degradation of chondroitin sulfate by these enzymes is distinct from that of testicular hyaluronidase, which produces saturated oligosaccharides. The study also describes the purification and properties of chondro-4-sulfatase and chondro-6-sulfatase, which are required for the desulfation of chondroitinase products. These enzymes have different substrate specificities. The results indicate that the degradation of chondroitin sulfates by these enzymes is not solely due to one enzyme but may involve multiple enzymes with different substrate specificities. The study also highlights the importance of understanding the specificity of these enzymes for elucidating the metabolic fate of mucopolysaccharides and for their potential use in determining the structure and quantity of mucopolysaccharides with high precision. The purification procedures and properties of these enzymes are detailed, including their substrate specificity and activity under various conditions. The study provides insights into the enzymatic degradation of chondroitin sulfates and the role of sulfatases in the desulfation process.The enzyme "chondroitinase-ABC" has been purified from Proteus vulgaris, NCTC 4636, which was adapted on a medium containing chondroitin sulfate C. It degrades chondroitin sulfates A, B, and C more efficiently than chondroitin and hyaluronic acid at pH 8. It catalyzes an elimination reaction, yielding Δ4,5-unsaturated disaccharides. It is accompanied by two sulfatases, chondro-4-sulfatase and chondro-6-sulfatase, which are required for the hydrolytic desulfation of chondroitinase products. Chondro-4-sulfatase converts Δ4,5-unsaturated disaccharide 4-sulfate to nonsulfated disaccharides, while chondro-6-sulfatase desulfates Δ6-sulfated disaccharides. Another chondroitinase, "chondroitinase-AC," has been purified from Flavobacterium heparinum, ATCC 13125, and shares similar properties with chondroitinase-ABC. It does not act on chondroitin sulfate B. Both enzymes degrade chondroitin sulfates A, B, and C via an elimination mechanism, producing Δ4,5-unsaturated disaccharides. The degradation of chondroitin sulfate by these enzymes is distinct from that of testicular hyaluronidase, which produces saturated oligosaccharides. The study also describes the purification and properties of chondro-4-sulfatase and chondro-6-sulfatase, which are required for the desulfation of chondroitinase products. These enzymes have different substrate specificities. The results indicate that the degradation of chondroitin sulfates by these enzymes is not solely due to one enzyme but may involve multiple enzymes with different substrate specificities. The study also highlights the importance of understanding the specificity of these enzymes for elucidating the metabolic fate of mucopolysaccharides and for their potential use in determining the structure and quantity of mucopolysaccharides with high precision. The purification procedures and properties of these enzymes are detailed, including their substrate specificity and activity under various conditions. The study provides insights into the enzymatic degradation of chondroitin sulfates and the role of sulfatases in the desulfation process.