Mannan between

Fig, 7.—Antiparallel packing arrangement of the 2-fold helices of mannan I (5). (a) Stereo view of two unit cells approximately normal to the fee-plane. The two comer chains (open bonds) in the back are not hydrogen bonded to each other. The antiparallel center chain (filled bonds) is linked to the left comer chain by 2-OH 0-5 bonds, (b) Projection of the unit cell along the c-axis the a-axis is down the page. This highlights the hydrogen bonds between the comer and center chains. 

Probit Equation The probit equation has been used in an attempt to quantitatively correlate hazardous material concentration, duration of exposure, and probability of effect/injury, for several types of exposures. The objective of such use is to transform the typical sigmoidal (S-shaped) relationship between cause and effect to a straight-line relationship (Mannan, Lees Loss Prevention in the Process Industries, 3d ed., p. 9/68, 2005). 

The difference in action patterns between these p-mannanases is shown clearly by fractionating and characterising the reaction products (Table I) (5). These products are a consequence of the abihty of the enzyme to cleave in the vicinity of D-mannosyl residues substituted by D-galactose, as well as the length of the 1,4-P-D-manno-oligosaccharide chain required by the enzyme for binding. The favoured conformation of the (l-4)-p-D-linked mannan chain is a flat... 

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).

In the present work, we extend the method to compensate for the hydrogen bonds present in carbohydrates. The hydroxylated character of carbohydrate polymers influences between-chain interactions through networks of hydrogen bonds that occur during crystallization. Frequently, several possible attractive interactions exist that lead to different packing arrangements, and several allomorphic crystalline forms have been observed for polysaccharides such as cellulose, chitin, mannan and amylose. The situation is even more complex when water or other guest molecules are present in the crystalline domains. Another complication is that polysaccharide polymorphism includes different helix shapes as well. 

Concanavalin A is an antibody-like protein isolated from the jack bean. 82 It was shown to form a precipitate with glycogen and with yeast mannan, and was later also used to differentiate between glycogen-like polysaccharides from various sources.283 284 It has now been shown that concanavalin A forms a precipitate only with branched polysaccharides which contain terminal, nonreducing a-D-glucopyranosyl or a-D-manno-pyranosyl groups.18 The combining sites of the protein appear to be directed against the 2-deoxy-a-D-aratano-hexopyranosyl system.2 ... 

Ellipsometry can follow the interactions between two types of biological macromolecules, the first of those two bound physically to the surface, the other acting from the solution. The binding of conconavalin A to adsorbed mannan 180) and of cholera toxin to adsorbed ganglioside t83) are examples. The adsorption of complement factors to an antibody-coated surface was monitored by ellipsometry and a modification of the same method was used for quantification of migration inhibition of human polymorphonuclear leucocytes 182). Interaction of proteins and cells with affinity ligands covalently coupled to silicon surfaces has been also studied 183). 

Out of 364 other tested enterobacteria 3 E. coli strains were positive, as were 8 of 9 Candida yeast isolates. These findings are not surprising because reciprocal cross-reactions between Salmonella Cl and some E. coli strains are well known (26) and in yeasts a mannan consisting of an a,l- -6 linked poly-D-mannose backbone with branches of a,l->-2 and a,l- -3 linked D-mannose residues is a principal cell-wall constituent (27). 

A very different structure has been found for the mannan that is present in yeast. Methylation and hydrolysis67 showed this to be a highly branched molecule. The methylated material was inhomogeneous, the intrinsic viscosity of different fractions varying between 0.062 and 0.212, with corresponding molecular weights (determined by osmotic pressure measurements) between 18,000 and 76,000 (90-830 hexose units). 

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