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If you have a question or need a quotation for your project using one of our services, please just fill out the Inquiry Form on the "Contacts" page, and we will do our best to respond to your inquiry within 24 hours.
A free online tool for protein cleavage sites prediction with a chosen enzyme.
Calculate monoisotopic and average mass of a custom peptide or peptides predicted from a protein.
The cleavage specificities of selected enzymes.
A comprehensive and freely accessible resource of protein sequence and functional information.
Mass spectrum simulation tool for peptide/protein sequences. The number of charge can be custom defined.
An online tool predicts m/z values for SMS ions generated from selected fragmentation methods such as CID, ECD, or ETD. The ion type and maximum number of charge can be pre-defined.
PDB provides the most complete collection of information about the 3D structures of proteins, protein complexes and other biomolecules.
Useful links
Frequently asked questions
1. How much sample do I need to provide for a HDX project?
The sample amount required might be dependent on the type of project, but about 0.1-1 mg sample is typically required for a HDX-MS project. The sample concentration is usually around 5-20 mg/ml for mAbs. If your sample does not meet these criteria, not a problem, please contact our scientists and they can always find a solution for you.
2. Does NovoAb provide discount for customers?
The goal of NovoAb Bioanalytics is to provide the highest quality protein characterization service at the most competitive prices. We are continuously optimizing our experimental workflows to reduce the time needed for each project, consequently lowering the cost for our customers. On the other hand, substantial discount is offered for mAbs that we have already analyzed, where the experimental time of the optimization step can be shortened as we already know the working conditions. Currently we are offering 10% discount for the following mAbs: Trastuzumab (Herceptin), Bevacizumab (Avastin), Adalimumab (Humira), Rituximab (Rituxan), Cetuximab (Erbitux), and Omalizumab (Xolair). We have also recently developed a simplified but effective workflow for fast epitope mapping service, if you need to quickly know the binding sites of a pool of antibodies, this would be a good option. Please contact us for more details.
3. What’s the advantage of running LC-MS at subzero temperature in HDX experiments?
The occurrence of back exchange has been described as “The single biggest problem with solution-phase H/D exchange”. Therefore, the chromatographic separation of the deuterium labeled peptides must be carried out under quench conditions and as fast as possible, to minimize the loss of deuterium caused by back exchange with the HPLC solvents. Even so, the back exchange in the traditional HDX workflow is still high (usually 10-50%), sometimes even higher for some specific peptides containing aspartic acid residues. The subzero temperature HPLC (e.g. -20 °C) designed for top-down and middle-down HDX-MS at NovoAb can significantly reduce the H/D back exchange to a minimal level (~2%), thus significantly improve the sensitivity and the structural information obtainable from HDX experiments.
4. What amount and purity of sample should I send for epitope mapping?
Normally 0.5 mg antigen is enough, but it also depends on the MW of the protein. Previously a purity of about 80% was required for the antigen, but now our newly developed NovoMap HDX-MS technology can handle unpurified antigens as well, even under conditions where your antigen is in a complex protein mixture and occupies only 10% of the total protein content. If you are unsure about your antigen, you can always e-mail us or give us a call.
5. What purity and amount of sample should I send for antibody paratope mapping?
The purity of your mAb sample should be normally > 80% and the amount we need is typically 1-2 mg. However, we have recently developed a proprietary workflow at NovoAb that can deal with unpurified mAbs. If your mAb sample is less than 80% pure, you are welcome to discuss with our scientists and they will advise you on how to proceed.
6. Can NovoAb do MW determination for ADCs?
Yes, we can do accurate molecular weight determination for various proteins, including intact antibodies and ADCs. The drug load and DAR can also be determined for whole ADC molecule, as well as for individual light chain and heavy chain.
7. How is NovoAb’s HDX-MS epitope mapping different from other epitope mapping methods?
A systematic comparison of various epitope mapping methods including peptide scanning, phage display, HDX-MS, and X-ray crystallography, was conducted using the same antigen-antibody complex, and the results were published on the top journal PNAS. HDX-MS epitope mapping was concluded to be the most effective method to rapidly supply complete information about epitope structure. A brief comparison of the results is summarized in the figure shown below (red bars in each panel represent the epitope residues determined by each method). The full article can be found at PNAS's website (http://www.pnas.org/content/110/9/3304). At NovoAb we have made significant improvements to the traditional HDX-MS method and developed our proprietary FineMapping technology, which can reach single amino acid resolution. The FineMapping platform works for both linear and conformational epitopes, with 100% successful rate.
