Band 3 anion exchanger

Band 3 Anion exchanger 95 K I Anion transport binding sites for ankyrin, protein 4.2... 

Liu DS, Kennedy SD and Knauf PA (1996) Source of transport site asymmetry in the band-3 anion exchange protein determined by NMR measurements of external Cr affinity. Biochemistry 35 15228-15235. 

Theory. The anion exchange resin, originally in the chloride form, is converted into the nitrate form by washing with sodium nitrate solution. A concentrated solution of the chloride and bromide mixture is introduced at the top of the column. The halide ions exchange rapidly with the nitrate ions in the resin, forming a band at the top of the column. Chloride ion is more rapidly eluted from this band than bromide ion by sodium nitrate solution, so that a separation is possible. The progress of elution of the halides is followed by titrating fractions of the effluents with standard silver nitrate solution. 

The major proteins (which include spectrin, ankyrin, the anion exchange protein, actin, and band 4.1) have been studied intensively, and the principal features of their disposition (eg, integral or peripheral), structure, and function have been established. 

The anion exchange protein (band 3) is a transmembrane glycoprotein, with its carboxyl terminal end on the external surface of the membrane and its amino terminal end on the cytoplasmic surface. It is an example of a multipass membrane protein, extending across the... 

In common with M. macedonicus, urine from male M. spretus also demonstrated a MUP-sized band following gel electrophoresis. The proteins within this band were analysed by high resolution anion exchange chromatography and electrospray ionisation mass spectrometry (ESI-MS). The former technique produced an elution profile consisting of just three peaks, in contrast to both the more complex patterns observed previously from M. m. domesticus and the single major peak in M. macedonicus. Furthermore, similar analyses from five individual males resulted in near... 

The average DS as determined by these methods provides only the simplest characterization of these derivatives, and further analysis was necessary to characterize the mixture of SBE bands of different levels of substitution. Due to the presence of the anionic sulfonate substituent, it is possible to use capillary electrophoresis (23), to separate the SBE-CD substitution bands and to characterize the fingerprint of the composition (Fig. 10). Anion exchange chromatography (24) was utilized to isolate separate substitution bands (mono- to deca-derivatives) that were subsequently identified by NMR and fast atom bombardment mass spectroscopy (FAB-MS). 

Figure 9 shows the purification of another l c-compound in a partially purified extract of goat milk. At this stage at least seven other anions are visible to the ultraviolet detector as the components are separated on Permaphase AAX anion exchanger. Even now the strong UV band almost directly above the radioactive peak appears to belong to a contaminant rather than the C-compound itself, indicating that further work will be required. 

Apparatus Use a suitable high-performance liquid chromatography system (see Chromatography, Appendix IIA) equipped with a dual wavelength detector system such that the effluent can be monitored serially at 254 nm and 325 to 385 nm (wide-band pass). Use a 1-m x 2.1-mm (id) column, or equivalent, packed with a strong anion-exchange resin (Dupont No. 830950405, or equivalent). 

An aliquot containing about 0.01 me 0s1B1 Is added to a small column (l ml) of anion exchange resin which had been treated with 6 N BC1. The Os complex absorbs as a reddish brown band at the top of the resin bed. When 6 N HC1 Is rapidly forced through the bed with a hypodermic syringe, a short-lived activity of Ir191 Is found In the effluent. 

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