Learn how to use this product 10x Buffer R is a 10x concentrated Strep-Tactin® regeneration buffer containing HABA (2-[4'-hydroxy-benzeneazo]benzoic acid). HABA displaces desthiobiotin from the modified biotin-binding pocket of Strep-Tactin® after elution. Upon binding of HABA to Strep-Tactin®, the yellow buffer turns red, which indicates regeneration and column activity. The 10x Buffer R is also available as part of the Strep-Tactin® Buffer Set (IB 2-1002-001).