title: Investigation of the interactions between ginsenosides and amino acids by mass spectrometry and theoretical chemistry.
abstract: In order to evaluate the essence of the interactions of ginsenosides and proteins which are composed by alpha-amino acids, electrospray ionization mass spectrometry was employed to study the noncovalent interactions between ginsenosides (Rb(2), Rb(3), Re, Rg(1) and Rh(1)) and 18 kinds of alpha-amino acids (Asp, Glu, Asn, Phe, Gln, Thr, Ser, Met, Trp, Val, Gly, Ile, Ala, Leu, Pro, His, Lys and Arg). The 1:1 and 2:1 noncovalent complexes of ginsenosides and amino acids were observed in the mass spectra. The dissociation constants for the noncovalent complexes were directly calculated based on peak intensities of ginsenosides and the noncovalent complexes in the mass spectra. Based on the dissociation constants, it can be concluded that the acidic and the basic amino acids, Asp, Glu, Lys and Arg, bound to ginsenosides more strongly than other amino acids. The experimental results were verified by theoretical calculations of parameters of noncovalent interaction between ginsenoside Re and Arg which served as a representative example. Two kinds of binding forms, "head-tail" ("H-T") and "head-head" ("H-H"), were proposed to explain the interaction between ginsenosides and amino acids. And the interaction in "H-T" form was stronger than that in "H-H" form.
authors.affiliation: College of Chemistry, Jilin University, Changchun 130012, PR China.
authors.forename: Chenling
authors.initials: C
authors.lastname: Qu
authors.forename: Liming
authors.initials: L
authors.lastname: Yang
authors.forename: Songcheng
authors.initials: S
authors.lastname: Yu
authors.forename: Song
authors.initials: S
authors.lastname: Wang
authors.forename: Yuping
authors.initials: Y
authors.lastname: Bai
authors.forename: Hanqi
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000378:metabolism*; D001665:Binding Sites; D036145:Ginsenosides / Q000032:analysis / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000596:Amino Acids; D036145:Ginsenosides