Biotin

Biotin is a water-soluble B-complex vitamin, also known as vitamin B7 or vitamin H. It binds to the biotin-binding pockets of streptavidin, Strep-Tactin(R), and Strep-Tactin(R)XT with different affinities. As a result, it allows the efficient elution of Strep-tag(R)II or Twin-Strep-tag(R) fusion proteins from Strep-Tactin(R)XT, while maintaining the reusability of the resin. It can be used for preparation of Strep-Tactin(R)XT elution buffer, Buffer BXT. In addition, biotin can be used for elution of biotinylated proteins from Strep-Tactin(R), where it binds irreversibly to the resin. Hence, Strep-Tactin(R) cannot be regenerated in this kind of application.