Isolation and characterization of a chondroitin sulfate-degrading endo-beta-glucuronidase from rabbit liver.
An endo-beta-glucuronidase acting on chondroitin sulfate was isolated from rabbit liver and purified about 550-fold, using a combination of ammonium sulfate fractionation, DEAE-cellulose chromatography, gel filtration on Sephacryl S-300, affinity chromatography through heparin-Sepharose CL-6B and preparative polyacrylamide gel electrophoresis. The pH optimum of this enzyme was 4.0 and the Km value 7 X 10(-3) M for chondroitin sulfate (Mr 40,000). The isoelectric point of the enzyme was found to be at pH 5.4. The molecular weight, estimated by gel filtration through Sephacryl S-200 and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was 35,000. This enzyme, which was found in the liver, kidney, spleen, and lung, hydrolyzed the glucuronyl galactose linkage of the linkage region of chondroitin sulfate possessing a very small peptide segment. The enzyme did not hydrolyze proteoglycan. It was concluded that an endo-beta-glucuronidase is involved in the catabolism of proteoglycan chondroitin sulfates.
Takagaki
K
K
Department of Biochemistry, Hirosaki University School of Medicine, Japan.
Nakamura
T
T
Majima
M
M
Endo
M
M
D000818:Animals; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005966:Glucuronidase / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D009928:Organ Specificity; D011134:Polysaccharides; D011817:Rabbits; D013379:Substrate Specificity
D011134:Polysaccharides; D005966:Glucuronidase