Diferric transferrin reduction by K562 cells. A critical study

Alajos Bérczi, Joseph A. Sizensky, Frederick L. Crane, W. Page Faulk

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

This paper critically examines the redox activity of K562 cells (chronic myelogenous leukemia cells) and normal peripheral blood lymphocytes (PBL). Ferricyanide reduction, diferric transferrin reduction, and ferric ion reduction were measured spectrophotometrically by following the time-dependent changes of absorbance difference characteristic for ferricyanide disappearance and for the formation of ferrous ion: chelator complexes. Bathophenanthroline disulfonate (BPS) and ferrozine (FZ) were used to detect the appearance of ferrous ions in the reaction mixtures when diferric transferrin or ferric ion reduction was studied. Special attention was devoted to the analysis of time-dependent absorbance changes in the presence and absence of cells under different assay conditions. It was observed and concluded that: (i) FZ was far less sensitive and more sluggish than BPS for detecting ferrous ions at concentrations commonly used for BPS; (ii) FZ, at concentrations of at least 10-times the commonly used BPS concentrations, seemed to verify the results obtained with BPS; (iii) ferricyanide reduction, diferric transferrin reduction and ferric ion reduction by both K562 cells and peripherial blood lymphocytes did not differ significantly; and (iv) earlier values published for the redox activities of different cells might be overestimated, partly because of the observation published in 1988 that diferric transferrin might have loosely bound extra iron which is easily reduced. It is suggested that the specific diferric transferrin reduction by cells might be considered as a consequence of (i) changing the steady-state equilibrium in the diferric transferrin-containing solution by addition of ferrous ion chelators which effectively raised the redox potential of the iron bound in holotransferrin, and (ii) changing the steady-state equilibrium by addition of cells which would introduce, via their large and mostly negatively charged plasma membrane surface, a new phase which would favor release and reduction of the iron in diferric transferrin by a ferric ion oxidoreductase. The reduction of ferricyanide is also much slower than activities reported for other cells which may indicate reduced plasma membrane redox activity in these cells.

Original languageEnglish
Pages (from-to)562-570
Number of pages9
JournalBBA - General Subjects
Volume1073
Issue number3
DOIs
Publication statusPublished - Apr 9 1991

Fingerprint

K562 Cells
Ions
Ferrozine
Oxidation-Reduction
Iron
Chelating Agents
Lymphocytes
Cell membranes
Cell Membrane
Blood
diferric transferrin
Leukemia, Myelogenous, Chronic, BCR-ABL Positive
Oxidoreductases
Observation
bathophenanthroline disulfonic acid
Assays
Cells
hexacyanoferrate III

Keywords

  • Bathophenanthroline disulfonate (BPS)
  • Diferric transferrin
  • Ferricyanide
  • Ferrozine
  • K562 cell
  • Redox activity

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

Diferric transferrin reduction by K562 cells. A critical study. / Bérczi, Alajos; Sizensky, Joseph A.; Crane, Frederick L.; Faulk, W. Page.

In: BBA - General Subjects, Vol. 1073, No. 3, 09.04.1991, p. 562-570.

Research output: Contribution to journalArticle

Bérczi, Alajos ; Sizensky, Joseph A. ; Crane, Frederick L. ; Faulk, W. Page. / Diferric transferrin reduction by K562 cells. A critical study. In: BBA - General Subjects. 1991 ; Vol. 1073, No. 3. pp. 562-570.
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