title: Colorimetric determination of glucosamine and glucose based on the formation of blue molybdosilicate anion and its application to the assay of saccharifying enzyme.
abstract: A simple and convenient method of reducing monosaccharide assay is proposed. A Si(IV)-Mo(VI) solution (pH 4.9) was yellow due to the formation of the 11- and/or 12-molybdosilicate(VI) anions. By the addition of a reducing saccharide, glucosamine, the mixture turned to blue gradually, indicating that the Mo(VI) species was reduced by the saccharide to form a blue molybdosilicate anion. The molybdenum blue formation occurred more quickly when a water-miscible organic solvent, dimethyl sulfoxide, was added to the Si(IV)-Mo(VI) solution. Thus, 0.01% level glucosamine can be determined colorimetrically with microtiter plate. Oligochitosan would not interfere with the determination of the glucosamine at the same concentration. Also, a remarkable blue color development of the Si(VI)-Mo(VI) solution was observed by the addition of glucose. On the other hand, maltose, cellobiose, and water-soluble starch at the same concentration level gave no significant coloration of the reaction mixture. Thus, the present monosaccharide assay can be applied advantageously to evaluate the saccharification to produce glucosamine and glucose.
authors.affiliation: Department of Bioscience, Fukui Prefectural University.
authors.forename: Hajime
authors.initials: H
authors.lastname: Katano
authors.forename: Shu
authors.initials: S
authors.lastname: Taira
authors.forename: Kohei
authors.initials: K
authors.lastname: Uematsu
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kimoto
mesh_terms: D000838:Anions / Q000737:chemistry / Q000378:metabolism; D003124:Colorimetry; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism*; D005944:Glucosamine / Q000032:analysis* / Q000378:metabolism; D005947:Glucose / Q000032:analysis* / Q000378:metabolism; D008982:Molybdenum / Q000737:chemistry* / Q000378:metabolism; D012825:Silicon / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000838:Anions; D008982:Molybdenum; D005087:Glucan 1,4-alpha-Glucosidase; D005947:Glucose; D005944:Glucosamine; D012825:Silicon