Galactomannan preparation

Ara, V., Thaler, H., Studies on coffee and coffee substitutes. XIX. Dependence of the quantity of a highly polymeric galactomannan on the degree of extraction of commercially prepared coffee-extracts, Z. Lebensm.-Unters. Forsch., 164, 8, 1977. (CA87 51829f)... 

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. 

Hylin and Sawai219 reported that the crystalline depolymerase from Leucaena leucocephala converts the galactomannan from the same source into D-galactose and D-mannose. Hence, it is most likely that the enzyme preparation contained /3-D-mannosidase activity, in addition to a-D-galactosidase and /3-D-mannanase activities. 

Guar gum is a galactomannan, commonly used in cosmetics, food products, and pharmaceutical formulations. It has also been investigated in the preparation of sustained-release matrix tablets in the place of cellulose derivatives such as methylcellu-lose. ... 

Figure 4 Thermal stability of lysozyme-polysaccharide conjugates. O, lysozyme , lysozyme-dextran conjugate , lysozyme-galactomannan conjugate. Lysozyme-polysaccharide conjugates were prepared by dry heating at 60°C for 2 weeks. Sample solutions (0.1%) in 67 mM phosphate buffer (pH 7.4) were heated at an increasing rate of l°C/min. The resulting turbidity was measured with the absorbance at 500 nm.

Cytoplasmic Peptidophosphogalactomannan. Fungal peptido-galactomannans have been extracted from powdered preparations (43). However, we were unable to obtain phosphogalactomannan from the cell walls of 3-day cultures of charlesii (20). When we examined extracts of P. charlesii cells we found galactofurano-syl residues both in a soluble cytoplasmic and a membrane-bound cytoplasmic fraction. 

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