Coupling Antibodies to Protein A or G

1. Use 2 mg of antibody per ml wet beads (use appropriate antibody/protein A or G combination).
   
   
2. Mix antibodies with beads and bind at room temperature for at least 1 hour (on roller).
   
   
3. Wash the beads twice with 10 volumes of 0.2 M Na-borate, pH 9.0; spin each time for 3 minutes at 4000 rpm.
   
   
4. Resuspend beads in 10 volumes of 0.2 M Na-borate, pH 9.0 .
   
   
5. Remove equivalent of 10 ul beads .
   
   
6. Add solid DMP (dimethylpimelimidate) to a final concentration of 20 mM [52 mg for 10 ml].
   
   
7. Mix on roller for 30 minutes at room temperature.
   
   
8. Remove equivalent of 10 ul beads.
   
   
9. Stop reaction by washing the beads twice in 0.2 M ethanolamine pH 8.0.
   
   
10. Incubate on roller for 2 hours at room temperature in 0.2 M ethanolamine pH 8.0.
    
    
11. Wash beads twice with PBS buffer.
    
    
12. Beads can be stored in PBS buffer at 4^oC.
    
    
13. Check coupling by analysing the before and the after sample on a 10% SDS gel.