Showing papers on "Keratan sulfate published in 1973"

Purification and Properties of a Keratan Sulfate Hydrolyzing Enzyme, An Endo-β-Galactosidase

Abstract: A keratan sulfate hydrolyzing enzyme was isolated from Coccobacillus, Chase, ATCC 13939, a non-gram-negative soil organism. The crude enzyme u as extracted by disruption of the cells, purified by ammonium sulfate fractionation, followed by DEAE- and CM-cellulose column chromatography and Bio-Gel P-100 gel filtration. The final preparation showed 113 times the specific activity of the original extract. The enzyme IS a basic protein, has an optimum pH at 5.5 and a temperature optimum at 32°C. It is an endo-β-D-galactosidase and splits KS§ into a series of sulfated oligosaccharides and sulfated peptido-oligosaccharides. The enzyme activity is inhibited by heavy metal ions, but not by EDTA anti dithiothreitol.The enzyme was assayed by measuring the trubidity produced by the reaction of KS with Hyamine. The enzyme unit was expressed as half turbidity, after 30 minutes or incubation with 200 μg of KS at pH 5.5 and 31°C. One unit of enzyme activity was contained in 9.7 μg of the purified enzyme fraction. The ass...

Glycosaminoglycan turnover and synthesis in the rat incisor pulp.

Abstract: – The rate of in vivo turnover and in vitro synthesis of the glycosaminoglycans (GAGs; acid mucopolysaccharides) of the dental pulp loose connective tissue from rat maxillary incisors has been investigated by isotope methods. The biologic half-life of 35SO4 in whole tissue digests was found to be 4.5 d. Of the sulfated GAGs the chondroitin-4-sulfate fraction was shown to have a more rapid turnover in vivo than the chondroitin-6-sulfate fraction, 4.1 and 5.2 d, respectively. The fraction containing keratan sulfate and glycoproteins had a biologic half-life of 6.8 d. Slices of rat incisor pulps were incubated in vitro with 35SO4 and the rate of incorporation into the different GAG fractions was determined. After a lag-phase of 15 min, this rate was linear with time. The chondroitin-6-sulfate fraction showed a more rapid uptake than the chondroitin-4-sulfate fraction, and the uptake by keratan sulfate + glycoprotein fraction was much lower. A similar in vitro experiment using [14C] acetate was performed. Contrary to the sulfate incorporation there was an extended lag-phase, and the total incorporation was much lower.