Oligosaccharides by enzymes

Extending Synthetic Routes for Oligosaccharides by Enzyme, Substrate and Reaction Engineering... 

Subsequently, a combined organic-enzymic approach was proposed for the synthesis of oligosaccharides. By common organic procedures, a... 

Figure 5. 22.63-MHz C-13-NMR spectra of (a) agarose (4a.) (b) neoagaro-oligo-saccharides ("lb, n = 3.9) produced by enzymic hydrolysis of 4a with p-agarase and (c) agaro-oligosaccharides ( 4c, n = 2.5) produced by enzymic hydrolysis of 4a with u-agarase. Spectra recorded in DgO solution at 33°C (3b,5c) or 93°C (5a). G = D-galactose, A = 3,6-anhydro-h-galactose.

How, exactly, retinol affects protein glycosylation is not yet known, but the formation of retinol phosphate, the D-mannosylation of retinol phosphate by GDP-Man, and the transfer of Man from D-mannosyl (retinol phosphate) to pronase-sensitive glycoconjugates are well established.5857,59 On the other hand, the formation and role of other gly-cosyl esters of retinol phosphate are still controversial.2,80 It is very probable that the D-mannosylation of retinol phosphate, and also the transfer of Man from this lipid derivative to protein, are catalyzed by enzymes different from those involved in the dolichol pathway,81-83 and this finding points to the different physiological roles of Man-P-Dol and D-mannosyl (retinol phosphate). Thus, whereas Man-P-Dol can serve to D-mannosylate dolichol diphosphate-linked oligosaccharides (see Section III), such a role has not been found for D-mannosyl (retinol phosphate).81,83... 

The rate data on the hydrolysis of different oligosaccharides by the almond glucohydrolase are shown in Table II. These data can be interpreted to indicate that the active site for the enzyme is composed of two subsites. Apparently the active site is so located on the enzyme that additional glucose residues in the substrate interfere with the binding of the substrate to the active site. 

Figure 13. Taper chromatogram of the hydrolysis products from cello-oligosaccharides by Ex-1. Developed by the descending technique for 72 hr at room temperature on Whatman No. 1 paper, using 1-butanol pyridine water (6 4 3, v/v) as a solvent (S) standard, (Gt) glucose, (Ge) cellobiose, (Gs) cellotriose, (Gu) cellotetraose, (G5) cellopentaose, (G6) cellohexaose final enzyme concentration 3.0 X 10 2%.

The mechanism responsible for improved detection is thought to be better accessibility of glycotopes to the antibody glycotopes usually are masked by unrelated large oligosaccharides. The enzyme treatment eliminates steric hindrance by these oligosaccharides. The mechanism of antigen retrieval essentially is based on the depolymerization of... 

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