Question (20877) | Annexin V/ANXA5-Cy3 Apoptosis Staining / Detection Reagent (ab14143)

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Question

Regarding you annexin V-Cy3 conjugate, I would like to know the following: 1) What is the source of your annexin? (e.g. human placenta?) 2) Is the annexin in ab14143 purified and labeled in Abcam labs? Or is the annexin V-y3 conjugate purchased from another company and repackaged in Abcam vials? If so, which company? 3) What is the protein:dye mole ratio? 4) Where, specifically which amino acids(s), on the protein is the Cy3 dye coupled to and by which chemistry (e.g. NHS ester coupling)? 5) What method do you use to verify the binding activity of annexin V-Cy3? I also purchased annexin V-Cy3 from Sigma Aldrich and the scientist I talked to was kind enough to give me all the above information I am now requesting from you. I'm not looking to steal anyone's methods. But since we don't have time or expertise here to do annexin isolation, purification, and labeling I need to buy it. For my experiments, I require knowing the information I'm requesting above. Without this information, there are too many unknowns and I cannot use the annexin product. I look forward to your reply.

Answer

Thank you for your enquiry. Please find below the answers to your questions. 1) The source of the annexin is human recombinant protein. 2) This product is from an originator outside of Abcam. Unfortunately, due to company policies and supplier agreements, we are not able to disclose the supplier information. 3) The protein:dye ratio is, 1 PROTEIN:4 DYE 4) The dye binds randomly to the lysine amino acid. 5) We use the annexin V-Cye3 on apoptotic Jurket cell and watch for red color expression around the cells on a flow cytometer. If there is anything else that I can help you with, please do not hesitate to contact me.

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