Description Application Biotin picolyl azide is a linker with an azide group for attachment to alkynes, a biotin for capture by streptavidin, and a picolyl group for faster azide reactivity. The picolyl azide chelates Cu(I) to enhance the reactivity of the azide-alkyne cycloaddition.[1][2] This is an advantage especially when working with low concentrations of alkynes and can also enable reduction of the copper concentration.