PrDiAzK is a bifunctional amino acid. PrDiAzK can be site-selectively incorporated into proteins in both bacterial and mammalian cell culture. PrDiAzK can be used for proteome-wide incorporation via stochastic orthogonal recoding of translation (SORT) [1]. PrDiAzK is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.