摘要：Dehydrochlorination of D-glucosamine (2-amino-2-deoxy-D-glucose) hydrochloride with an anion exchange resin made its DNA breaking activity in plasmid pBR322 much higher, especially in the presence of Cu2+. The sample of anion exchanger-treated D-glucosamine hydrochloride, i.e., HCl-free D-glucosamine sample, showed an absorption maximum at 274 nm on the UV absorption spectrum in water as seen in the case of fructosazine [2, 5-bis (D-arabino-tetrahydroxybutyl) pyrazine], one of the dimers of D-glucosamine. On a positive-ion fast atom bombardment (FAB) mass spectrum, the sample showed an ion peak at m/z 323 as a base peak, corresponding to dihydrofructosazine [2, 5-bis (D-arabino-tetrahydroxybutyl) dihydropyrazine], which was a precursor of fructosazine, as well as those of D-glucosamine itself (m/z 180) and fructosazine (m/z 321). The DNA strand breaking activity of HCl-free D-glucosamine sample was directly proportional to the peak intensity of m/z 323 ion, while the DNA breaking activity of fructosazine was much weaker than that of HCl-free D-glucosamine sample. 2, 5-Dihydro-3, 6-dimethylpyrazine and 2, 3-dihydro-5, 6-dimethylpyrazine having a dihydropyrazine skeleton the same as dihydrofructosazine showed the same extent of DNA strand breaking activity as did the HCl-free D-glucosamine sample. These results indicated that dihydrofructosazine produced during the dehydrochlorination is closely involved in the DNA breaking activity of HCl-free D-glucosamine sample.
关键词：D-glucosamine;dihydrofructosazine;dihydropyrazine skeleton;DNA breaking activity;cupric ion;FAB mass
