Biotin-PEG-Alk (MW 10000) is a biotin labeled PEG derivative. Biotin is an enzyme co-factor, can be used for labeling protein; PEG is a hydrophilic and water-soluble polymer with low toxicity; Alk (Alkyne), acyclic (branched or unbranched) aliphatic hydrocarbon, can react with azido, which improve the efficiency of biotin binding targets. Biotin-PEG-Alk (MW 10000) is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.