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Factors that influence siderophoremediated iron bioavailability: catalysis of interligand iron (III) transfer from ferrioxamine B to EDTA by hydroxamic acids.

Publication ,  Journal Article
Monzyk, B; Crumbliss, AL
Published in: Journal of inorganic biochemistry
August 1983

Deferriferrioxamine B (H3DFB) is a linear trihydroxamic acid siderophore with molecular formula NH2(CH2)5[N(OH)C(O)(CH2)2C(O)NH(CH2)5]2N(OH)C(O)CH3 that forms a kinetically and thermodynamically stable complex with iron(III), ferrioxamine B. Under the conditions of our study (pH = 4.30, 25 degrees C), ferrioxamine B, Fe(HDFB)+, is hexacoordinated and the terminal amine group is protonated. Addition of simple hydroxamic acids, R1C(O)N(OH)R2 (R1 = CH3, R2 = H; R1 = C6H5, R2 = H; R1 = R2 = CH3), to an aqueous solution of ferrioxamine B at pH = 4.30, 25.0 degrees C, I = 2.0, results in the formation of ternary complexes Fe(H2DFB)A+ and Fe(H3DFB)A2+, and tris complexes FeA3, where A- represents the bidendate hydroxamate anion R1C(O)N(O)R2-. The addition of a molar excess of ethylenediaminetetraacetic acid (EDTA) to an aqueous solution of ferrioxamine B at pH 4.30 results in a slow exchange of iron(III) to eventually completely form Fe(EDTA)- and H4DFB+. The addition of a hydroxamic acid, HA, catalyzes the rate of this iron exchange reaction: (formula; see text) A four parallel path mechanism is proposed for reaction (1) in which catalysis occurs via transient formation of the ternary and tris complexes Fe(H2DFB) A+, Fe(H3DFB)A2+, and FeA3. Rate and equilibrium constants for the various reaction paths to products were obtained and the influence of hydroxamic acid structure on catalytic efficiency is discussed. The importance of a low energy pathway for iron dissociation from a siderophore complex in influencing microbial iron bio-availability is discussed. The system represented by reaction (1) is proposed as a possible model for in vivo catalyzed release of iron from its siderophore complex at the cell wall or interior, where EDTA represents the intracellular storage depot or membrane-bound carrier and HA represents a low molecular weight hydroxamate-based metabolite capable of catalyzing interligand iron exchange.

Duke Scholars

Published In

Journal of inorganic biochemistry

DOI

EISSN

1873-3344

ISSN

0162-0134

Publication Date

August 1983

Volume

19

Issue

1

Start / End Page

19 / 39

Related Subject Headings

  • Mathematics
  • Iron
  • Inorganic & Nuclear Chemistry
  • Hydroxamic Acids
  • Ferric Compounds
  • Edetic Acid
  • Deferoxamine
  • Biological Availability
  • 3402 Inorganic chemistry
  • 0399 Other Chemical Sciences
 

Citation

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Monzyk, B., & Crumbliss, A. L. (1983). Factors that influence siderophoremediated iron bioavailability: catalysis of interligand iron (III) transfer from ferrioxamine B to EDTA by hydroxamic acids. Journal of Inorganic Biochemistry, 19(1), 19–39. https://doi.org/10.1016/0162-0134(83)85010-7
Monzyk, B., and A. L. Crumbliss. “Factors that influence siderophoremediated iron bioavailability: catalysis of interligand iron (III) transfer from ferrioxamine B to EDTA by hydroxamic acids.Journal of Inorganic Biochemistry 19, no. 1 (August 1983): 19–39. https://doi.org/10.1016/0162-0134(83)85010-7.
Monzyk, B., and A. L. Crumbliss. “Factors that influence siderophoremediated iron bioavailability: catalysis of interligand iron (III) transfer from ferrioxamine B to EDTA by hydroxamic acids.Journal of Inorganic Biochemistry, vol. 19, no. 1, Aug. 1983, pp. 19–39. Epmc, doi:10.1016/0162-0134(83)85010-7.
Journal cover image

Published In

Journal of inorganic biochemistry

DOI

EISSN

1873-3344

ISSN

0162-0134

Publication Date

August 1983

Volume

19

Issue

1

Start / End Page

19 / 39

Related Subject Headings

  • Mathematics
  • Iron
  • Inorganic & Nuclear Chemistry
  • Hydroxamic Acids
  • Ferric Compounds
  • Edetic Acid
  • Deferoxamine
  • Biological Availability
  • 3402 Inorganic chemistry
  • 0399 Other Chemical Sciences