title: Preparation of tea glycoprotein and its application as a calibration standard for the quantification and molecular weight determination of tea glycoprotein in different tea samples by high-performance gel-permeation chromatography.
abstract: Tea glycoprotein (TGC) was purified by Sephadex G-100 gel filtration, and its purity and molecular weight (MW) were determined by high performance gel permeation chromatography. The gel permeation chromatography (GPC) elution behavior of TGC on an Ultrahydrogel 500 (7.8x300 mm) column was studied using a mobile phase with various concentrations of NaCl. A dextran T system was found to be unsuitable as MW calibration standards in GPC because the MW of TGC was changed with the change of ionic concentration in the mobile phase. Thus, the purified TGC obtained in this study was standardized and used instead as the calibration standards for the determination and comparison of TGCs in tea samples collected from different geographic locations and species varieties. The GPC was run at 35 degrees C on an Ultrahydrogel 500 column (7.8x300 mm) with a refractive index detector. Distilled water was used as the mobile phase at a flow rate of 0.6 ml.min(-1). The calibration curve was linear over the TGC concentration range of 0.604-6.04 mg.ml(-1), with a correlation coefficient of r=0.9997. The TGC mass recovery ranged from 80.4 to 93.2%, with a relative standard deviation of 5.42%. The assay method developed in this paper was found to be simple, reproducible, and reliable and, thus, ideally suitable for the quality control of TGC-derived products and raw materials.
authors.affiliation: Key Laboratory of Food Science of Ministry of Education, Nanchang University, Nanchang 330047, P.R. China.
authors.forename: Shaoping
authors.initials: S
authors.lastname: Nie
authors.forename: Mingyong
authors.initials: M
authors.lastname: Xie
authors.forename: Yuanxing
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002138:Calibration; D002850:Chromatography, Gel / Q000379:methods*; D006023:Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification*; D008970:Molecular Weight; D010936:Plant Extracts / Q000737:chemistry*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013662:Tea / Q000737:chemistry*
chemical_list: D006023:Glycoproteins; D010936:Plant Extracts; D013662:Tea