Davids Biotechnologie GmbH
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When you want antibodies against a protein you only know the sequence from or antibodies against proteins that are hard to express we can help you. In this case we have a look at the protein sequence and predict the immunogenicity, hydrophilicity and perform epitope predictions of certain peptide sequences. These peptide sequences represent the protein and antibodies are made against these peptides and usually you receive some very good antibodies.
As the 3D-structure of the proteins and other non-predictable factors can play an important role in the antibody production we can not guarantee that the antibodies will work. But you can raise your chance by using two or three peptides that are derived from the same protein sequence.
Another useful application of peptide antibodies is that they should only recognize the specific peptide sequence. Here you might be able to detect proteins from a family: see Pepitde Alignment.
Using two or more peptides
When you use two different peptides you have the choice to immunize one rabbit for each peptide or two mix the peptides and immunize one rabbit with both peptides. We recommend to immunize only one rabbit with both peptides, but to make two affinity purifications afterwards, one with the first peptide, the other one with the second peptide. In this case you receive two different antibody fractions. Of course you can immunize a second animal with both peptides too, to increase the product amount.
Peptide Synthesis & Quality Control
After you confirmed that you want to order one or more peptides we start the synthesis of the peptide. HPLC and MS are done for quality control.
For the antibody production a peptide purity of >70% is sufficient. Nevertheless we can synthesize peptides with higher purity. Please ask for this service.
Conjugation to a carrier
After the synthesis we start the conjugation to a carrier molecule like KLH (Keyhole Limpet Hemocyanin). This is important as the peptides only have a small molecular mass. The carrier protein has a good antigenicity and a high mass. This ensures the optimal presentation of the antigen. The peptides are cross-linked with i. e. glutaraldehyde, which reacts with the amino acids from the carrier and the peptide to form a heterogenous conjugate.
In every case you receive an aliquot of the synthesized peptide. If you ordered antibodies, we conjugate as much peptide as needed for all immunizations.
Peptide Sequence Prediction & Selection
First you send us the protein sequence from your protein - of course we handle your data confidentially. Then we predict the immunogenicity, hydrophilicity, accessibility and make some epitope predictions for free and suggest you peptides that are suitable for the antibody production. This is done with computer algorithms from our scientists that analyze the protein sequence. The lenght of the peptides is usually 15 - 20 amino acids, but more or less amino acids per peptide are possible, though less than 10 is not recommended.
More than one peptide
To enhance the chance to get the best possible antibodies against your native protein, we suggest you to use more than one peptide from one protein. This raises the chance to get good antibodies from 70% (one peptide) over 90% (two peptides) to 97% (three peptides). In mind with the accessibility it is helpful to choose one peptide from the N-term and the other from the C-term or from the middle of the protein, so that the chance increase that the final antibody can reach the epitope.
The chance that the final antibodies recognize the protein and not only the peptide
There is always a small chance that the antibodies do not recognize the original full-lenght protein. Things like the protein structure play an important role in the antibody recognition. To enhance the chance to get good antibodies against the full-lenght protein check: Peptide Antibodies
Distinguish between two similar proteins
We can help you with protein alignments when you try to avoid that the antibodies show a cross-reactivity against proteins from another similar or the same family. As this is a very complex application we can not guarantee that the final antibodies only recognize one of the aligned proteins.
In this case we have a look at both sequences (or even more) and make an alignment. We suggest you some peptide parts that are as unique as possible. In addition it helps to use more than one peptide and to purify the final serum to raise the chance to get useful antibodies.
Peptide Antibody Purification