Hexosamines, determination

Ishihara, K., Kameyama, J. -I., and Hotta, K., Development of an HPLC method to estimate hexosamines and its application to determine mucin content in rat and human gastric mucosa, Comp. Biochem. Physiol., 104B, 781, 1993. 

Although widely used, colorimetric methods for determining total ur-onic acid and hexosamine are now regarded as providing, at best, only semi-quantitative estimates of heparin.42 Colorimetric reactions in a strong acid, such as the carbazole reaction for the uronic acids48 and the Morgan-Elson reaction for the hexosamines,49 are not specific for hepa-... 

Boas, N. F. Method for the Determination of Hexosamines in Tissues. J. biol. 

The neomycin molecule does not exhibit fluorescence but following suitable de-rivatisation two spectrofluorimetric determinations have been described. Maeda et al l reported the complexation of simple hexosamines with pyridoxal and zinc ions to result in a fluorescent derivative. Applying this procedure to neomycin, Simpsonl32 demonstrated a linear response over the concentration range 0-50 yg/ml of neomycin sulphate. 

Radioactive acetate is a cheaper, readily available precursor for experiments on the labelling of sialic acid in tissues or cells, and it effectively labels the N- and O-acyl groups of sialic acids.228 This method is of great value not only for the preparation of radioactive sialic acids having high specific radioactivity but also for metabolic studies of sialic acids. However, the sialic acids must be isolated before determination of the specific radioactivity, as other aeetylated hexosamines are also labelled. 

Cornforth, J.W. and Firth, M.E. 1958. Identification of two chromogens in the Elson-Morgan determination of hexosamines. A new synthesis of 3-methylpyrrole. Structure of the pyrolene-phthalides . J. Chem. Soc. 1091-1099. 

Deamination of the hexosamine molecule occurs on heating it with alkali,205 and determination of the ammonia evolved is the basis of one quantitative method for the determination of 2-amino-2-deoxy-D-glucose.206 Deamination of 2-amino-2-deoxy-D-glucose with nitrous acid leads to the formation of 2,5-anhydro-D-mannose ( chitose ), which can be isolated as the crystalline diphenylhydrazone.207 Reduction of 2,5-anhydro-o-man-... 

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