D-mannan

P-D-mannan with single 6-Unked a-D-galactose branches g 4)-p -D-glucomannan ... 

Note. A less branched D-galacto-D-mannan could be shown in the short form as ... 

The slightly galactosylated mannans are essentially linear polymers. As a result of their cellulose-like (1 4)-/3-D-mannan backbone, they tend towards self-association, insolubility, and crystallinity. Crystallographic study of C. spectabilis seed GaM [180] with a Man Gal ratio 2.65 1 suggested an orthorhombic unit cell with lattice constants of a = 9.12, b = 25.63, and c = 10.28 the dimension b was shown to be sensitive to the degree of galactose substitution and the hydration conditions [180 and references therein, [191]]. 

Benzyl derivatives of (1 6)-a-D-glucan, (l->6)-a-D-mannan, and (l-> 6)-a-D-galactan have been studied in 1,4-dioxane. These derivatives have complex and interesting c.d. spectra due to the ww transition of the chromophore with resolved vibrational structure. However, a conformational interpretation of these interesting spectra is not possible at this time. 

Comparison of Endolytic Hydrolases That Depolymerize l,4- d-D-Mannan, 1,5-a-L-Arabinan, and 1,4- -D-Galactan... 

The most characterised D-mannan degrading enzymes are the endo- -mannanases (5). These enzymes act on a range of 1,4-p-D-mannan-type polysaccharides including D-mannan, glucomannans (acetylated and deacetylated), galactomannans and galacto-glucomannans. The extent and... 

Assay and Purification of p-Mannanases. p-Mannanase can be specifically measured in crude enzyme mixtures with a dye-labelled carob galactomannan substrate (6), This substrate has a galactose content high enough (23%) to impart solubility to the substrate, but sufficiently low as not to interfere with the action of p-mannanases on the D-mannan backbone. The soluble dye-labelled substrate is incubated with enzyme preparation under controlled conditions and the reaction is terminated and unreacted dyed polysaccharide precipitated by ethanol addition. 

Figure 1. Schematic representation of subsite binding between / -mannanase and the (1— 4)-/ -D-mannan chain. (Reproduced with permission from reference 5. Copyright 1983 Elsevier Science Publishers).

Because of its inhibition of the formation of Man-P-Dol and GlcNAc-PP-Dol, diumycin may be useful in attempts to discover possible roles of Glc-P-Dol in D-glucan formation, because it would block concomitant formation of D-mannan and glycosylation of proteins. 

Limited, X-ray diffraction evidence suggested that the chain is a 2(1.52) helix, with an uncoordinated variation about this average conformation. As the projected height of the trisaccharide repeat-unit is 1.52 nm, the average advance per saccharide is 0.507 nm, similar to that in cellulose and D-mannan. 

The linear polysaccharides have been used in a number of immunological reactions. The linear D-mannan was found to confer cutaneous activity in guinea pigs to a dermatophyte polysaccharide.136 It was, however, found to be non-cross-reactive with antibodies to yeast D-mannan,137-138 and antibodies to linear D-mannan were not cross-reactive to yeast D-mannan.138 Anti-linear-D-mannan antibodies have been... 

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