GK16S is a UCHL1 chemogenomic probe. GK16S can be used as a complement to GK13S. GK16S and GK13S can be used to study UCHL1 function in cells. GK16S is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.