A New Bromobimane Fluorescent Label for Anion Exchange Proteins
A new, negatively charged fluorescent labeling agent, sulfobenzoyloxybromobimane (SBBr), selectively labels the membrane anion exchange protein (Band 3) in intact erythrocytes under physiological conditions. The fluorescent product is stable and easily seen after electrophoretic separation of proteins from solubilized membranes (whole membranes or membranes stripped of peripheral proteins). Quantitation is carried out with solubilized membranes or by densitometry of the gel. Chloride ions diminish the rate of labeling. Diisothiocyanatostilbenedisulfonate (DIDS) inhibits labeling by SBBr. The major part of the label remains in the 60kDa fragment after chymotrypsin treatment of SBBr-labeled cells. SBBr-binding site(s) may be different from those attacked by DIDS. SBBr is useful for studying band 3 and related proteins, including C1- channels.
KeywordsErythrocyte Ghost Human Erythrocyte Membrane Peripheral Protein Intact Erythrocyte Inhibit Anion Transport
Unable to display preview. Download preview PDF.
- Jessen F, Søholm C, Hoffmann EK (1986) Identification of the anion exchange protein of Ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-dihydjostilbene-2,2′-disulfonate ( DIDS) and labeling of membrane proteins with H-DIDS. J Membrane Biol 92: 195–205CrossRefGoogle Scholar
- Lodish HF (1988) Anion-exchange and glucose transport proteins: Structure, function and distribution. Harvey Lec. 82: 19–46Google Scholar
- Sheetz MP, Schindler M, Koppel DE (1980) Lateral mobility of integral membrane proteins is increased in spherocytic erythrocytes. Nature 285, 510– 512Google Scholar