Work

Myoplasmic binding of fura-2 investigated by steady-state fluorescence and absorbance measurements

Year: 1988

Type: article

Abstract: Binding of the fluorescent Ca2+ indicator dye fura-2 by intracellular constituents has been investigated by steady-state optical measurements. Fura-2's (a) fluorescence intensity, (b) fluorescence emission anisotropy, (c) fluorescence emission spectrum, and (d) absorbance spectra were measured in glass capillary tubes containing solutions of purified myoplasmic proteins; properties b and c were also measured in frog skeletal muscle fibers microinjected with fura-2. The results indicate that more than half, and possibly as much as 85%, of fura-2 molecules in myoplasm are in a protein-bound form, and that the binding changes many properties of the dye. For example, in vitro characterization of the Ca2+-dye reaction indicates that when fura-2 is bound to aldolase (a large and abundant myoplasmic protein), the dissociation constant of the dye for Ca2+ is three- to fourfold larger than that measured in the absence of protein. The problems raised by intracellular binding of fura-2 to cytoplasmic proteins may well apply to cells other than skeletal muscle fibers.

Source: Biophysical Journal

DOI: 10.1016/s0006-3495(88)83045-5

Authors: M. Konishi, A. Olson, S. Hollingworth, S.M. Baylor

Institution: University of Pennsylvania

Language: English

Topic: Advanced Fluorescence Microscopy Techniques

Subfield: Biophysics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $3,000

Funder: National Institute of Neurological Disorders and Stroke