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Affinity Chromatography - Department of Molecular and Cellular ...

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Options<br />

Product Spacer Coupling conditions Maximum Comments<br />

arm<br />

operating flow<br />

CNBr-activated None pH 7–9, 2–16 hours, 400 cm/h* Supplied as a freeze-<br />

Sepharose 4 Fast Flow +4 °C - room temp. dried powder.<br />

CNBr-activated None pH 8–10, 2–16 hours, 75 cm/h* Supplied as a freeze-<br />

Sepharose 4B +4 °C - room temp. dried powder.<br />

*See Appendix 4 to convert linear flow (cm/h) to volumetric flow rate. Maximum operating flow is calculated from<br />

measurement in a packed column with a bed height <strong>of</strong> 10 cm <strong>and</strong> i.d. <strong>of</strong> 5 cm.<br />

There are many examples in the literature <strong>of</strong> the use <strong>of</strong> CNBr-activated Sepharose.<br />

Figure 61 shows the separation <strong>of</strong> a native outer envelope glycoprotein, gp120, from HIV-1<br />

infected T-cells. Galanthus nivalis agglutinin (GNA), a lectin from the snowdrop bulb, was<br />

coupled to CNBr-activated Sepharose 4 Fast Flow to create a suitable affinity medium.<br />

A 280 nm<br />

0.5<br />

native gp120<br />

0<br />

24 hours 40 min Time<br />

Fig. 61. Separation <strong>of</strong> native gp120 protein on GNA coupled to CNBr-activated Sepharose 4 Fast Flow.<br />

From Gilljam, G. et al., Purification <strong>of</strong> native gp120 from HIV-1 infected T-cells. Poster presented at Recovery <strong>of</strong><br />

Biological Products VII, Sept. 25-30, 1994, San Diego, CA, USA. Further details are available in the CNBr-activated<br />

Sepharose 4 Fast Flow datafile, from Amersham Pharmacia Biotech.<br />

Buffer preparation<br />

Acidification solution: 1 mM HCl (kept on ice)<br />

Coupling buffer: 0.2 M NaHCO 3 , 0.5 M NaCl, pH 8.3<br />

Blocking buffer: 1 M ethanolamine or 0.2 M glycine, pH 8.0<br />

Wash buffer: 0.1 M acetate, 0.5 M NaCl, pH 4<br />

Preparation <strong>of</strong> CNBr-activated Sepharose 4 Fast Flow <strong>and</strong> CNBr-activated Sepharose 4B<br />

1. Suspend the required amount <strong>of</strong> freeze-dried powder in ice-cold 1 mM HCl (HCl preserves the activity <strong>of</strong> the<br />

reactive groups that hydrolyze at high pH).<br />

2. Wash for 15 min. on a sintered glass filter (porosity G3), using a total <strong>of</strong> 200 ml 1 mM HCl per gram dry<br />

powder, added <strong>and</strong> sucked <strong>of</strong>f in several aliquots. The final aliquot <strong>of</strong> 1 mM HCl is sucked <strong>of</strong>f until cracks<br />

appear in the cake.<br />

3. Transfer the matrix immediately to the lig<strong>and</strong> solution.<br />

109

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