Chondroitin sulfate, hydrolysis

Dermatan sulfate, also termed chondroitin sulfate B, a related glycosaminoglycan constituent of connective tissue, was known to be composed of galactosamine and a uronic acid, originally believed to be glucuronic acid but then claimed to be iduronic acid based largely on color reactions and paper chromatography. However, the d or L-enantiomer status of the latter monosaccharide was not clear. Jeanloz and Stoffyn unequivocally characterized the monosaccharide as L-iduronic acid by consecutive desulfation, reduction, and hydrolysis of the polysaccharide, followed by isolation of the crystalline 2,3,4-tri-0-acetyl-l,6-anhydro-/ -L-idopyranose, which was shown to be identical to an authentic specimen synthesized from 1,2-0-isopropylidene-/ -L-idofuranose.34... 

This enzyme [EC 3.1.6.18], also known as glucuronate-2-sulfatase and chondro-2-sulfatase, catalyzes the hydrolysis of the 2-sulfate groups of the 2-O-sulfo-D-glucuro-nate residues of chondroitin sulfate, heparin, and hepari-tin sulfate. The enzyme does not act on iduronate 2-sulfate residues. 

FIGURE 1 Potential hydrolysis rates of six structurally distinct polysaccharides in seawater (A) and surface sediments (B) from Skagerrak and Svalbard. Pull = pullulan, lam = laminarin, xyl = xylan, fu = fucoidan, ara = arabinogalactan, chon = chondroitin sulfate. Note the differences in scale on the y axes for sediments and for seawater. [Skagerrak data from Arnosti (2000).]... 

Ji, D. et al. Determination of chondroitin sulfate content in raw materials and dietary supplements by high-performance liquid chromatography with ultraviolet detection after enzymatic hydrolysis single-laboratory validation. J. AOAC Int. 2007, 90, 659-669. 

Chondroitin 4- and 6-sulfates were originally designated as chondroitin sulfate A and C, respectively, and the close similarity in structure between them is demonstrated by the fact that both mucopolysaccharides yield the same disaccharide (chondrosine) on controlled, acidic hydrolysis together with sulfuric and acetic acids. Chondroitin 4-sulfate or chondroitin 6-sulfate, or both, occur in cartilage and adult bone, and the former mucopolysaccharide is a minor constituent of ligamentum nuchae and cornea (M17). Chondroitin 6-sulfate is a minor constituent of umbilical cord and occurs with dermatan sulfate (chondroitin sulfate B) and hyaluronic acid in heart valves and adult connective tissue (M17). An acid mucopolysaccharide isolated from human plasma resembles chondroitin 4-sulfate in its properties (S4). 

The current method for the hyaluronidase assay described in the United States Pharmacopeia (USP) [132] is based on the inability of hydrolyzed potassium hyaluronate to form a complex precipitate with proteins from added serum, reflected in a decreased turbidity of the reaction mixture (measured after 30 min). The method is, from the enzymological point of view, not well defined since it does not actually evaluate the kinetics of the hydrolysis of the substrate. An assay with end-point determination is only valid if the reaction rate does not change during this reaction time. We found that only with the two lowest test concentrations (0.15 and 0.3 IU) was this condition fulfilled, while with the three higher test concentrations the reaction is not linear. Commercially available hyaluronates can be contaminated with chondroitin sulfates. They are more acidic than hyaluronic acid itself and hence can form better protein complexes and influence the turbidity. In a suitability test of the USP [133], the substrate must pass both an inhibitor content test and a turbidity-production test. The assumption is made that... 

It is well known that dietary fat is not absorbed from the intestine unless it has been subjected to the action of pancreatic lipase [1], Previously, we found that basic proteins such as protamines, histones and purothionine inhibited the hydrolysis of triolein emulsified with phosphatidylcholine [2], The inhibition of hydrolysis of dietary fat may cause a decrease or delay in the intestinal absorption of fat and reduce blood chylomicron levels, an excess of which is known to induce obesity [3], Therefore, there was a possibility that inhibitory substances toward pancreatic lipase activity may prevent the onset of obesity induced by feeding a high fat diet to mice. Recently, we found that natural products such as tea saponin, platycodi radix saponin, chitin-chitosan and chondroitin sulfate inhibited the pancreatic lipase activity. In the following section, the anti-obesity effects of these natural products will be described in detail. 

As shown in Fig. (14), chondroitin sulfate inhibited the pancreatic lipase activity dose-dependently at the concentrations of 1-20 mg/ml in the assay system using triolein emulsified with phosphatidylcholine at 10 mg/ml it inhibited triolein hydrolysis by about 60%. On the other... 

Y. Liu, T. He, C. Gao, Surface modification of poly(ethylene tere-phthalate) via hydrolysis and layer-by-layer assembly of chitosan and chondroitin sulfate to construct cytocompatible layer for human endothelial cells. Colloids Surf. B Biointerfaces 46 (2) (2005) 117-126. 

Chondroitin, the nonsulfated polysaccharide, has been isolated from the corneal hyaluronosulfate fraction of Meyer (54a), It appears to be the desulfated chondroitin sulfate A or C. Chondrosine, the disaccharide obtained by the acid hydrolysis of this chondroitin, has an infrared absorption spectrum identical with that of the chondrosine of chondroitin sulfate A. An unsaturated acid is present in the disaccharide isolated following the action of pneumococcal hyaluronidase on chondroitin and desulfated chondroitin sulfate (54b),... 

The presence of both glucuronic add and a-linkages in heparin and heparitan sulfate results in a polysaccharide resistant to hydrolysis, and the uronic acid part is decarboxylated before the amino sugar part is completely released. Similar difficulties are encountered in the hydrolysis of chondroitin 4- and 6-sulfates (chondroitin sulfates A and C), whereas dermatan sulfate ()8-heparin, chondroitin sulfate B) can be hydrolyzed under conditions mild enough to allow the isolation of iduronic add. 

Hydrolysis of dermatan sulfate with strong mineral acid afforded equal molecular amounts of acetic acid, sulfuric acid and D-galactosamine. In contrast to the molecule of chondroitin sulfate, the molecule of dermatan sulfate is far more susceptible to hydrolysis, and treatment with dilute acid did not afford a disaccharide, but an undegraded uronic add. Paper chromatographic analysis indicated that it was similar to iduronic acid , which explains the low intensity of the color shown by dermatan sulfate in the carbazole reaction. 

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