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Q
Is it usually the N terminal or the C terminal of the protein that is chosen to make antibodies?
To avoid the risk of the recognition region being hidden within the protein, it is usually recommended to select the N and C ends of the protein to produce the corresponding antibody. Because in a complete protein, the N and C ends are usually exposed to the surface of the protein. However, it must be noted that the C-terminus of the membrane protein is too hydrophobic to be suitable as an antigen.
Q
Can antiserum be tested in western blot using peptide antigen as a positive control?
The molecular weight (MW) of the peptide antigen (unbound) is too small to be used in traditional western blotting (WB) tests. To verify the specificity of target bands in WB, it is recommended to run an "antibody block" control and use peptide antigen to block the primary antibody. The recommended bleeding dilution is 1:1000 (equal to 1µg/ml) and the blocking peptide is about 2µg/ml.
Q
How do you define a good antibody?
A quality antibody is one that has the appropriate sensitivity and specificity to answer the questions your test poses. In addition, one antibody is not necessarily suitable for all applications, as each application has different performance specifications.
Q
How do you decide whether to choose a monoclonal antibody or a polyclonal antibody?
Both polyclonal and monoclonal antibodies have their own advantages. Generally speaking, monoclonal antibodies have strong specificity, but relatively small affinity, and relatively low sensitivity to detect antigens. The specificity of polyclonal antibody is weak, but the affinity of the antibody is strong and the sensitivity is high. Compared to monoclonal antibodies, large quantities of polyclonal antibodies are relatively quick and inexpensive to produce, and they are nonspecific because they are able to recognize multiple epitopes on any one antigen.
Q
Does the company provide any guarantee for the customer's custom monoclonal antibody service?
For qualified protein antigens, ChinaPeptides can guarantee two ELISA and WB positive clones against the immunogen. For qualified peptide antigens, ChinaPeptides can guarantee two positive clones, the ELISA results against the immunogen are positive. For other cases, ChinaPeptides will provide assurance based on the immune response after immunization.
Q
What are the protein-expression systems of the flamboyant organisms?
ChinaPeptides Co., Ltd. has successfully built a complete platform of various protein expression technologies, including prokaryotic protein expression and purification, yeast protein expression and purification, insect cell protein expression and purification, mammalian cell protein expression and purification.
Q
What are the advantages of the customized protein service?
With more than 10 years of experience in protein expression and a successful delivery rate of over 96%, we provide one-stop services from gene synthesis, vector construction, gene expression, protein purification and detection to meet customers' individual needs.
Q
How to choose the right protein expression system?
Different protein expression systems are selected according to the customer protein source (bacterial, animal or other) and the purpose of the purified protein. If you do not know how to choose, please consult online customer service, we will wholeheartedly recommend the right expression system for customers.
Q
How are protein services and long chain polypeptide services defined?
<50aa is generally used for peptide synthesis, >50aa peptide synthesis is difficult to try to express.
Q
What are the impurities in the protein expression process?
Impurities are mostly in cells or in the medium and can be removed by chromatography.
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