BN QuickPickTM CM
For the rapid fractionation of protein

    

The weak cation exchange method in the Bio-Nobile QuckPickTM CM kit us based on magnetic cellulose particles coated with carboxymethyl (CM) groups.  Different types of proteins will bind to the CM coated magnetic particles with affinities  that depend on both the conditions used and the types and number of individual charged groups.  Typically a mixture of numerous proteins, for example cell lysate, is used as a sample with ion exchangers.  After unbound molecules are washed away, the composition of the buffer is changed by altering the pH and salt concentration to release the molecule(s) of interest from the particles.
Proteins consist of many different amino acids, and the overall charge is caused by the composite effect of many different ionisable groups.  The pH at which the protein has no net charge is called the isoelectric point, and termed pI.  The pI of most proteins is in the range of 5-9. Ion-exchange of proteins is typically performed at least 1 pH unit away from the pI of the protein of interest.  When the pH is below the pI, the molecule will be positively charged and a cation exchange resin should be used.  When the pH is above the pI, the molecule will be negatively charged and an anion exchange resin should be used.  Since interactions of ion-exchange groups with proteins depend on the surface charges of the protein, even a protein at its pI may bind to the ion exchange matrix.

In the purification of proteins, a low buffer concentration must be used during binding otherwise the buffer components will compete with the proteins for the exchange sites.

BN QuickPickTM CM  protocol
Number tubes 1 to 6 
Tube 1 : 100 mL CM magnetic particles in storage solution
Tube 2 :  400 mL CM Regeneration Buffer
Tube 3 :  400 mL CM Wash Buffer
Tube 4 :  300 mL sample
Tube 5 : 400 mL CM Wash Buffer
Tube 6 :   50 mL CM Elution Buffer

   Protocol
  1. Collect CM magnetic particles from Tube 1 with PickPen and regenerate them by releasing into tube  Tube 2 (CM Regeneration Buffer).  Mix the suspension in Tube 2 for 10 seconds.
  1. Collect magnetic particles from Tube 2 with PickPen and release them into Tube 3 (CM Wash Buffer). 
  1. Collect magnetic particles from Tube 3 with PickPen and release them into Tube 4  (sample).  Mix the magnetic particles thoroughly and incubate for 2 minutes.  Mix occasionally to avoid sedimentation.
  1. Collect the magnetic particles from Tube 4 with PickPen and wash them in Tube 5 (CM Wash Buffer) by releasing the particles into the solution.  Mix the suspension in Tube 5 for 10 seconds.  
  1. Collect the magnetic particles from Tube 5 with Pickpen and release them into Tube 6 (CM Elution Buffer) and mix thoroughly.  Incubate for at least 1 minute mixing  occasionally.
  1. After incubation collect the magnetic particles  from Tube 6 and discard.  The sample is now in the eluate and ready to be used for downstream applications.

 

Aprotinin purification using
BN QuickPickTM CM

 

QuickPickTM CM Catalogue Number   No of Preparations
CM Kit BN 62201 8 preps
CM Kit BN 62211 48 preps

For details of the PickPenTM magnetic transfer device click here

 

FOR RESEARCH USE ONLY - NOT FOR USE IN DIAGNOSTIC PROCEDURES

     

Metachem Diagnostics Ltd.
29 Forest Road, Piddington, Northampton. NN7 2DA
Tel. (01604) 870370     Fax (01604) 870194