The galactose oxidase borohydride procedure for labeling gangliosides has been substantially improved. The experiments were performed on monosialoganglioside GM1. The rate and extent of ganglioside GM1 oxidation by galactose oxidase was greatly enhanced using high substrate concentrations (over 1.0 mM) and adding adequate amounts (0.75%) of a proper detergent, Triton X 100. Under these conditions the enzyme easily affects the ganglioside micelle, probably of the mixed type (ganglioside plus detergent). The further treatment with potassium borohydride H3 yielded a ganglioside carrying 1.31x105 c.p.m./nMole. 90% of radioactivity was incorporated by the galactose residue located in terminal position within the ganglioside molecule; a much lower but not negligible amount of radioactivity was also present in the galactose and N acetylgalactosamine moieties present in inner position. This finding makes consistent the possibility to label oligosialogangliosides by a similar procedure.
|Number of pages||9|
|Journal||Italian Journal of Biochemistry|
|Publication status||Published - 1974|
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