Purification and structure of the major product obtained by reaction of NADPH and NMNH with the myeloperoxidase/hydrogen peroxide/chloride system.
The first spectrophotometric study of the reaction of the myeloperoxidase/H2O2/Cl- system with NADPH and NMNH showed that the reaction products were not the corresponding oxidized nucleotides and that modifications would take place on the nicotinamide part of the molecule [Auchère, F. & Capeillère-Blandin, C. (1999) Biochem. J. 343, 603-613]. In this report, in order to obtain more precise information on the structural modifications and mechanism of the reaction, we focus on the purification and isolation of products derived from NADPH and NMNH by RP-HPLC. Electrospray ionization mass spectra indicated that the relative height of the peaks reflected that of the natural isotopic abundance of 35Cl and 37Cl, providing evidence that the products derived from NADPH and NMNH were monochlorinated. Moreover, calculated masses revealed the 1 : 1 addition of HOCl to the molecule. Various 1D and 2D NMR experiments provided data for the assignments of the chemical shifts of protons and carbons and the coupling constants of the protons of the chlorinated nucleotides. Further NOESY experiments allowed the characterization of the spatial structure of the chlorinated product and showed that trans HOCl addition occurred at the C5=C6 carbon double bond of the nicotinamide ring, leading to a chlorohydrin.
Auchère
F
F
Laboratoire de Chimie et Biochimie pharmacologiques et toxicologiques (UMR 8601CNRS), Université Paris 5, France.
Bertho
G
G
Artaud
I
I
Girault
J P
JP
Capeillère-Blandin
C
C
D002244:Carbon / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry*; D002728:Chlorohydrins / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D008958:Models, Molecular; D009249:NADP / Q000737:chemistry* / Q000378:metabolism*; D009537:Nicotinamide Mononucleotide / Q000737:chemistry* / Q000378:metabolism*; D009195:Peroxidase / Q000737:chemistry*; D011485:Protein Binding; D011687:Purines / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013053:Spectrophotometry; D013997:Time Factors
D002712:Chlorides; D002728:Chlorohydrins; D011687:Purines; D009537:Nicotinamide Mononucleotide; D009249:NADP; D002244:Carbon; D006861:Hydrogen Peroxide; D009195:Peroxidase