6-((6-((BIOTINOYL)AMINO)H 25 MG，B6352，Invitrogen

Biotin-XX, SSE reacts efficiently and reproducibly with amines. The biotin is well separated from the point of attachment by a 14-atom spacer consisting of two, seven-atom aminohexanoyl groups (X). This spacer enhances the accessibility of biotin to the relatively deep biotin-binding sites of avidin and streptavidin. The sulfonate group on the succinimidyl ester increases the water solubility of the reactive moiety.