| Glycoprotein are a kind of macromolecule compounds with complicate structure, which has various biological activities,and play important roles in the organism. In this paper, sweet potato as raw material,was purified, and studied physical and chemical nature and structure of the water-soluble glycoprotein by chromatography, gel electrophoresis and infrared scanning technology. Based on bovine serum albumin (BSA), Dextran T70 (DT70) and extracted water-soluble glycoprotein from sweet patoto as samples, the methods were established that the water-soluble glycoprotein was detected by high-performance gel chromatography (HPGC),diode array detector (DAD) and evaporative light-scattering detector (ELSD) in series.Conclusion are as follow:(1) Single factor test and orthogonal test of L9 (34 ) were used in this paper to determine the best result. The best extraction condition of water-soluble glycoprotein was that the ratio of sample to water was 1: 25, the temperature of extraction was 40℃, the time of extraction was 1 hour and pH was 9. This powder of water-soluble glycoprotein was white, soluble easily in the water. It was hardly soluble in methanol, acetone and other organic solvents. Its molecular mass was 66,000Da.It was 88.23% for protein content and 11.75% content for sugar. It contained the non-starch class polysaccharide, the acetyl amino, the pyranose link and Alpha the sugar glucoside key. Afterβ-elimination reaction, it had the obvious absorption peak in 240nm. So it was the O-glycoprotein. The water-soluble glycoprotein from sweet potato was indicated in vitro: It had the good anti-lipin peroxidation function.(2) The chromatographic conditions of HPGC-DAD-ELSD in series to identify the purity of water-soluble glycoprotein were as follows:the mobile phase was pure water; the best mobile phase flow rate was0.5ml/min,the best column temperature was 30℃,the best configuration drift tube temperature was 80℃,the pressure of carrier gas was 0.35Psi.(3) Qualitatively and quantitatively analysis on BSA and DT70 by HPGC-DAD-ELSD in series showed, non-conjugated protein and polysaccharide can be separated by HPGC, two peaks were showed on ELSD chromatogram, and the availability of the retention time and a qualitative analysis can be certained by DAD. The highest correlation coefficient of linear equations of BSA on 280nm was:R2=0.9999;the formula was:LogA= 0.9488LogC +3.4377.In the ELSD on the peak area the best correlation coefficient equation of BSA was:R2 = 0.9981,and the formula was:LogA = 1.3649LogC +6.6932. In the ELSD on the peak height of the good correlation coefficient of linear equations of DT70 was:R2 = 0.999,and the formula was:LogA = 0.9139LogC +6.2925. Two recoveries range of BSA and DT70 were 95% ~ 103% . The minimum detections of bovine serum albumin and dextran were 50ng, 24ng respectively. The retention time of BSA in the ELSD detector laged DAD 0.13s.(4) Qualitative and quantitative analysis by HPGC-DAD-ELSD in series on the water-soluble glycoprotein showed that: with the high-performance gel chromatography in the diode array detector and evaporative light scattering detector chromatograms were only a single chromatographic peak.It showed that the protein and polysaccharide were covalently conjugated. In a given context,the log-linear equation of water-soluble protein in the diode array detector (215-225nm) from the peak height was:LogA =1.4051LogC+1.124,ELSD's peak area of the linear equation was:y=2E+09 x-5E+06.Respectively,the correlation coefficient were R2 = 0.9998 and R2 =0.9982 greater than 0.99,a good linear relationship. Recovery was in the 92%~103%.The detection limit of Sweet water-soluble glycoprotein minimum was 18ng. The method was simple,rapid, accurate and without derivation. It was a effective method. The chromatographic peak retention time of ELSD detector was late 0.13s.The HPGC-DAD-ELSD in series could be directly reflected the effect of removing protein and further proof of the purity of water-soluble polysaccharide.
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