Invitrogen™ NeutrAvidin Protein, DyLight™ 550

Avidin is a glycoprotein found in the egg white and tissues of birds, reptiles and amphibia. The biotin-binding protein contains four identical subunits having a combined mass of 67,000-68,000 daltons. Removing the glycosylation from avidin yields NeutrAvidin Protein with a mass of 60,000 daltons. Carbohydrate-based lectin-binding is reduced to undetectable levels, yet biotin-binding affinity is retained. NeutrAvidin Protein offers the advantages of a neutral pI to minimize nonspecific adsorption, along with lysine residues that remain available for derivatization or other customized conjugation. NeutrAvidin Protein yields the lowest nonspecific binding among the known biotin binding proteins. The specific activity for biotin-binding is approximately 14 μg/mg of protein, which is near the theoretical maximum activity.