Galactomannan oxidation, enzymic

Rogers and Thompson208 used the action of this enzyme, and subsequent oxidation by bromine, to effect the conversion of a galactomannan into a galacturonomannan a similar sequence has been used with glycoproteins as a method for linkage analysis.209... 

Newer assays involve the action of enzymes, e.g., the assay of Baird and Smith (1989b) who treated galactomannans with galactose oxidase to generate H202 that in turn oxidized o-tolidine in the presence of preoxidase. These authors claimed this double oxidation reaction to be specific for the galactosyl monomer and its derivatives, based on the exclusive oxidation at the C-6 position. o-Phenylenediamine can be substituted for o-tolidine the color is measured at 425 nm. 

Galactomannan has been modified to increase the solubility by oxidation with enzyme and 2,2,6,6-tetramethyl-l-piperidinyloxy radical (TEMPO).[24,25] Other derivatives are also available such as hydroxyethylgalactomannan, cationic or anionic galactomannans. [26-28] Grafted copolymers were also prepared by grafting acrylamide on cationic guar. [29,30]... 

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