Frequently asked questions about protein purifications
More questions, by subject area, here:
Frequently asked questions about the QuickPick technology and manual devices
Frequently asked questions about nucleic acid purifications
Frequently asked questions about protein purifications

What applications do you have for proteins?
For protein purifications we have different approaches for the purification strategy. First, we have fractionation kits such as QuickPick™ DEAE (using weak anion exchange) and QuickPick CM (using weak cation exchange). By using these kits you are able to enrich your target protein to a fraction containing also other proteins. This may be a good choice when you have a complex protein sample and need to do a prepurification step before actual purification. Secondly there are kits based on affinity chromatography such as IMAC (immobilized metal affinity chromatography) and GST (glutathione-S-transferase). IMAC affinity purification is based on the specific separation of histidine-tagged proteins and is one of the most widely used techniques up-to-date. Using BN Products & Services’ QuickPick IMAC Plus kit it is possible to purify up to 0.5 mg protein per preparation. The QuickPick GST glutathione affinity kit is intended for the purification of GST-fusion proteins. At least 40 µg of GST-fusion protein can be purified per preparation. All the protein kits are ready-to-use containing all the reagents needed for the purifications.

I would like to purify specific proteins from plant or other source. How could I apply your technology?
There are several approaches:

a) If you want to purify specific proteins from plant or other source you would need to have the specific Abs against them. In this case and if you will label the Abs with biotin you could use our Streptavidin magnetic particles for protein purification.

b) We also have magnetic particles based on ion-exchange properties. These would give you an opportunity to fractionate the proteins and enrich your target proteins to a certain level. You would need to have an analysis method (e.g. enzymatic, Western blot etc) for the identification of the correct target protein.

c) The next possibility is to clone the genes of the proteins (if you know their DNA sequences) in a His-tag or GST protein encoding expression vector and make a His-tag or GST fusion proteins out of them. In this case you could use our IMAC or GST kits for the purification of the proteins.

My his-tagged protein is expressed as insoluble inclusion bodies. Can I purify them with your technology?
Yes, by using our QuickPick IMAC or IMAC Plus kit the purification can be performed under strongly denaturing conditions in which the inclusion bodies are solubilized. A technical note for the protocol may be downloaded from our literature pages.

Is it possible to regenerate the magnetic particles used in protein purification kits?
The magnetic particle technology for protein purification is based on typical group specific and affinity chromatographic chemistries. The magnetic particle can be regenerated using conventional regeneration methods used in chromatography. However, BN Products & Services does not guarantee that results obtained by using regenerated magnetic particles are within the specifications defined for the kits.

After purification some of the target protein remained in the sample. Can I use the sample once again?
One of the great benefits of BN Products & Services' Bio-Nobile™ technology is that the sample remains for additional use, if needed. In this case you may repeat the purification with fresh reagents to obtain the rest of the target protein. If a concentrated target protein solution is needed the protein can be eluted in the same elution buffer that was used for the first purification.

Can you give me information about the binding capacity of the protein kits?
The binding capacities per preparation in our protein kits are as follows:
QuickPick CM: 60 µg ± 6 µg (aprotinin)
QuickPick DEAE: 60 µg ± 6 µg (BSA)
QuickPick IMAC: 30 µg ± 5 µg (His6-glutathione-S-transferase)
QuickPick IMAC Plus: 0.5 µg ± 50 µg (His6-glutathione-S-transferase)
QuickPick GST: 40 µg ± 4 µg (GST)

Does IMAC work with high salt concentrations?
In IMAC metal affinity method the salt concentration plays no role in binding His-tagged proteins. High salt concentration in sample might prevent unwanted proteins from binding to the particles. Instead the concentration on Imidazole is important: in low imidazole concentration (~5 mM) the His-tagged proteins bind to the particles. Then the particles are washed in a bit higher imidazole concentration (5-40 mM) to get rid of all the other proteins. And in high imidazole concentration (>300 mM) the His-tagged proteins will detach from the particles.