Linkages, cleaved

Ether linkage, cleaving of, 70 569 Ether oxygens, in association reactions, 70 682... 

A neutral, ninhydrin-positive, non-extractable (from aqueous media), viscous syrup. Rf in butanol-acetic acid-water, 0.32 (Rf values known in four other solvents). Hydroxamic linkage cleaved in 2 hrs at 50° in 0.5N HC1, yielding N8-hydroxyornithine. Reductive hydrolysis in 48%... 

Fig. 3. Substrate specificity of heparin lyases. The arrows indicate the glucosaminidic linkages cleaved by the enzymes. Both configurations of the carboxylate group are shown when both IdoA and GlcA are compatible with lyase action. An unsubstituted hydroxyl group at C-3 of the GlcN residue toward the reducing end is a prerequisite for susceptibility to lyases II and III. Other groups essential for cleavage with the indicated enzyme are shown in bold type. (Adapted from Ref. 98.)...

In the first case, the random attack on different molecules could lead to the steep d< /dRS curves described as more random by Nisizawa. In the second case, where more than one attack occurs on successive fragments of a single molecule, d< /dRS would be lower and would give the curves described as less random. In other words, the difference in the pattern of action of the enzymes, as measured by the slope of the d< /dRS curves, would depend upon the numbers of linkages cleaved per encounter between enzyme and substrate. 

Methane and CO were the only light products since phenolic hydroxyls were thermally stable. The yield of the former reached 0.010, whereas the maximum CO yield was 0.0064. After rapid decreasing to 0.43, as the reactive other linkages cleaved, the residue yield increased to 0.6 by 120 min while the single-ring product yield decreased. This was a result of the secondary reactions of the guaiacyl- and dihydroxyl-containing compounds to char. 

Although the linkages cleaved in macromolecular heparin were only tentatively identified, the enzyme appears to act on regions of the chain containing 2-acetamido-2-deoxy-D-glucosyl residues. D-Glucopyranosyluronic acid residues are exposed by the action of this enzyme, which is a heparin hydrolase (an endo-D-glucuronidase),... 

Hydrolysis of synthetic polysaccharides were investigated with an endo-acting dextranase. The percent of glycoside linkage cleaved was determined from the concentration of reducing sugars and expressed as the degree of hydrolysis. The maximum hydrolysis of a nonsubstituted dextran was 53%, and the main product was a disaccharide isomaltose. 

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