グルコースとアンモニアとの室温における非酵素的反応 : その反応機構
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This study has begun when ninhydrin-reactive compound was found to be produced at room temperature as soon as glucose and dibasic ammonium phosphate solutions were mixed. The reaction seemed to be similar to Maillard reaction. Therefore, the experiments have been performed to purify and determine the structure of the compound, glucose and dibasic ammonium phosphate were used throughout this experiment to produce the ninhydrin-reactive compound which is referred to as NR compound in this report. The reaction mixture was desalted in MicroAcilyzer and applied on cation-exchange resin, Dowex 50W-X8 column (H^+) at pH 2.0 to eliminate glucose. The NR compound adsorbed to the resin was eluted with 3.0 N HCl solution. Finally, the residual salt in the eluent was removed by gel-filtration method with Sephadex G-10 column and the eluent containing NR compound thus purified was concentrated in rotary evaporator at the temperature lower than 40℃. NR compound solution thus obtained have no glucose and almost no salts. The chemical structure of the NR compound was determined by amino acid analyzer, HPLC, FAB/MS, ion spray LC/MS and NMR. (a) The retension time of NR compound in amino acid analyzer was different from that of galactosamine but the same as that of glucosamine. However, reduced NR compound and reduced glucosamine were eluted at different time, (b) Mass spectrum of the NR compound produced by FAB/MS showed similar pattern to that of glucose. And both FAB/MS and ion spray LC/MS showed that the molecular weight of the compound was 179. (c) According to the result of NMR analysis, amino-residue binds to the carbon at position 1 of the compound and hydroxy residue binds to the carbon at position 2, 3 and 4. The position 1 and position 2 is in S-trans configuration. (d) Amino acid analyzer showed that the retention time of reduced NR compound and that of glucamine were the same. FAB/MS and ion spray LC/MS showed that molecular weight of the two compounds are the same (M. W. = 181). These results indicate that the peak of the NR compound observed by amino acid analyzer is Amadori product of Maillard reaction, 1-amino 1-deoxyfructose although some of the data suggested a possibility that it is the mixture of enol- and keto-form of Amadori products. since apparent NR compound was found in a patient suffering from hepatic coma due to hyperammonemia caused by liver cirrhosis, NR compound is possibly formed in patients with hyperglycemia and/or hyperammonemia and can play some physiological role in the patients. Not only in patients but also in normal subjects, the level of ammonia in portal vein is rather high and NR compound is possibly formed in the vein that affects the liver function in an unknown way.
- 北陸学院短期大学の論文
- 1994-12-27
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関連論文
- Purification and Heterogeneity of Human Chorionic Gonadotropin
- グルコースとアンモニアとの室温における非酵素的反応 : その反応の生理的意味
- グルコースとアンモニアとの室温における非酵素的反応 : その反応機構