title: NADH induces iron release from pea seed ferritin: a model for interaction between coenzyme and protein components in foodstuffs.
abstract: Plant ferritin from legume seeds co-exists with coenzyme NADH (a reduced form of nicotinamide-adenine dinucleotide) in many foodstuffs. In the present study, the interaction of NADH with apo pea seed ferritin (PSF) was investigated by fluorescence resonance energy transfer (FRET), fluorescence titration, transmission electron microscope (TEM), and isothermal titration calorimetry (ITC). We found that NADH molecules bound on the outer surface of PSF close to the 4-fold channels, which was 1.58 nm from tryptophan residue (Trp). Consequently, such binding facilitates iron release from holo PSF, which might have a negative effect on PSF as an iron supplement, while NADH was oxidised into NAD(+). However, the binding of NADH to the protein does not affect the entry of toxic ferrous ions into the apo protein shell, where these ferrous ions were oxidised into less toxic ferric ions. Moreover, NADH binding markedly affects the tertiary structure around Trp residues of PSF. These findings advanced our understanding of the interactions between different naturally occurring components in a complex food system.
authors.affiliation: CAU & ACC Joint-Laboratory of Space Food, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
authors.forename: Chenyan
authors.initials: C
authors.lastname: Lv
authors.forename: Yufei
authors.initials: Y
authors.lastname: Bai
authors.forename: Senpei
authors.initials: S
authors.lastname: Yang
authors.forename: Guanghua
authors.initials: G
authors.lastname: Zhao
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
mesh_terms: D001665:Binding Sites; D003067:Coenzymes / Q000737:chemistry / Q000378:metabolism*; D005293:Ferritins / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D009243:NAD / Q000737:chemistry / Q000378:metabolism*; D018532:Pisum sativum / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D012639:Seeds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003067:Coenzymes; D010940:Plant Proteins; D009243:NAD; D005293:Ferritins; D007501:Iron
keywords: FRET; Interaction; Iron release; NADH; Pea seed ferritin