Determination of noncovalent binding using a continuous stirred tank reactor as a flow Injection device coupled to electrospray ionization mass spectrometry

Santos, Inês C.Waybright, Veronica B.Fan, HuiRamirez, SabraMesquita, Raquel B. R.Rangel, António O. S. S.Fryčák, PetrSchug, Kevin A.2016-01-082016-01-082015SANTOS, Inês C.; WAYBRIGHT, Veronica B.; FAN, Hui; RAMIREZ, Sabra; MESQUITA, Raquel B.R.; RANGEL, António O. S. S.; FRYČÁK, Petr; SCHUG, Kevin A. - Determination of Noncovalent Binding Using a Continuous Stirred Tank Reactor as a Flow Injection Device Coupled to Electrospray Ionization Mass Spectrometry. Journal of the American Society for Mass Spectrometry. ISSN: 1044-0305. Vol. 26, N.º 7 (2015), p. 1204-12121044-0305http://hdl.handle.net/10400.14/18861Abstract. Described is a new method based on the concept of controlled band dispersion, achieved by hyphenating flow injection analysis with ESI-MS for noncovalent binding determinations. A continuous stirred tank reactor (CSTR) was used as a FIA device for exponential dilution of an equimolar host-guest solution over time. The data obtained was treated for the noncovalent binding determination using an equimolar binding model. Dissociation constants between vancomycin and AcLys(Ac)-Ala-Ala-OH peptide stereoisomers were determined using both the positive and negative ionization modes. The results obtained for Ac-L-Lys(Ac)-D-Ala-D-Ala (a model for a Gram-positive bacterial cell wall) binding were in reasonable agreement with literature values made by other mass spectrometry binding determination techniques. Also, the developed method allowed the determination of dissociation constants for vancomycin with AcL-Lys(Ac)-D-Ala-L-Ala, Ac-L-Lys(Ac)-L-Ala-D-Ala, and Ac-L-Lys(Ac)-L-Ala-L-Ala. Although some differences in measured binding affinities were noted using different ionization modes, the results of each determination were generally consistent. Differences are likely attributable to the influence of a pseudo-physiological ammonium acetate buffer solution on the formation of positively- and negatively-charged ionic complexes. Keywords: Binding constants, CSTR, Electrospray ionization mass spectrometry, Controlled band dispersion, Vancomycin, Alanine stereoisomersengBinding constantsCSTRElectrospray ionization mass spectrometryControlled band dispersionDetermination of noncovalent binding using a continuous stirred tank reactor as a flow Injection device coupled to electrospray ionization mass spectrometryjournal article10.1007/s13361-015-1113-21879-11238493490797825832030000356538500016