Fluorescence and Absorption Studies of the Binding of Copper and Iron to Transferrin
Year: 1969
Type: article
Abstract: A study has been made of the fluorescence and absorption changes that occur when Cu++ and Fe+++ bind to transferrin. Calculations of the overlap integrals and critical transfer distances involved show that the large fluorescence quenching produced by this binding is consistent with Forster long range energy transfer from tryptophan to absorption bands produced by the metal-protein interaction. A nonlinear dependence of fluorescence on metal binding was observed for iron but not for copper. This is also consistent with the Forster mechanism. Agreement between the experimental fluorescence results for iron binding and a phenomenological treatment with a random binding model is presented as evidence for independent and equivalent metal-binding sites in transferrin. Difference absorption spectra were obtained for the 250 to 600 mµ spectral range. Characteristic peaks in the region of tyrosine and tryptophan absorption indicated perturbation of these chromophores by the binding of metal ions.
Source: Journal of Biological Chemistry
Author: S S Lehrer
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1499054486