Alkynyl-biotin is a form of biotin with a terminal alkyne group separated by two polyethylene glycol moieties. It is used to add biotin to other molecules bearing an azide group using a copper Cu(I)-catalyzed azide-alkyne cycloaddition reaction. Alkynyl-biotin has been used to add a biotin tag to a range of biochemicals, amino acids, proteins, and nucleotides that have been modified by the addition of an azide group. Alkynyl-biotin can also be used to capture sulfenic acid-modified proteins that have been tagged with the cell-permeable probe DAz-2 .
