title: Study of the non-covalent interactions of ginsenosides and lysozyme using electrospray ionization mass spectrometry.
abstract: BACKGROUND
  Ginsenosides are an important class of natural products extracted from ginseng that possess various important biological activities. Studies of interactions of ginsenosides with proteins are essential for comprehensive understanding of the biological activities of ginsenosides. In this study, the interactions of ginsenosides with lysozyme were investigated by electrospray ionization mass spectrometry (ESI-MS).
  
  
  METHODS
  Both protopanaxadiol-type and protopanaxatriol-type ginsenosides were chosen to explore the interactions of ginsenosides towards lysozyme near the physiological conditions by direct ESI-MS, respectively. Comparative experiments were conducted to confirm the interactions were specific. In addition, the dissociation constants of ginsenoside-lysozyme complexes were determined by a ESI-MS titration strategy.
  
  
  RESULTS
  The results showed ginsenosides bound to lysozyme at the stoichiometries of 1:1 and 2:1. The association constants of ginsenosides to lysozyme were in the order of Re>Rd>Rf>Rg2 >Rg3 . According to their structures, the binding affinities associated with the type of aglycone and the type and the number of sugar moieties linked on the aglycone.
  
  
  CONCLUSIONS
  It has been demonstrated that ESI-MS is a powerful tool to probe the non-covalent interactions between lysozyme and ginsenosides. These results provide insights into the interaction of ginsenosides with lysozyme at the molecular level. The developed strategy could be applied to determine the interactions of proteins with other natural products.
authors.affiliation: Key Laboratory of Synthetic Rubber, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.|Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.|University of the Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Tang
authors.affiliation: Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.|University of the Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Key Laboratory of Synthetic Rubber, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.|Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Cui
authors.affiliation: Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.
authors.forename: Junpeng
authors.initials: J
authors.lastname: Xing
authors.affiliation: Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Changchun Center of Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, China.|Changchun University of Chinese Medicine, Changchun, 130117, China.
authors.forename: Shuying
authors.initials: S
authors.lastname: Liu
mesh_terms: D036145:Ginsenosides / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry*; D005894:Panax / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D036145:Ginsenosides; D010936:Plant Extracts; D009113:Muramidase