The Protein Man's Blog | A Discussion of Protein Research

Question:

What is protein labelling and what should you do to ensure a successful reaction?  

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Last week we reviewed some key factors to consider when coupling a label (biotin) to a protein.  The main factors considered were:

Biotin, a 244 Dalton vitamin (Vitamin H) molecule, exhibits an extraordinary binding affinity for avidin (Ka=10¹⁵M^-1) and streptavidin. Biotin and avidin interaction is rapid and once the bond is established it can survive up to 3M guanidine-hydrochloride and extremes of pH.