Fig. 1: Reaction of biotin-hydrazide with protein intermediates generated by LOXs-catalysis.
Oxidative deamination catalyzed by lysyl oxidases (LOXs) leads to collagen crosslinking by spontaneous condensation. Intermediate semialdehyde and the imine and aldol products of the crosslinking reaction can be labeled by biotinylated hydrazide. LOXs oxidize lysine and hydroxylysine side chains on collagen and elastin to highly reactive semialdehydes called allysines, while producing hydrogen peroxide (H2O2) and ammonia (NH3) as byproducts. Allysines then spontaneously condense to form cross-linkages. In our approach to detect LOXL2 activity, adding biotin-hydrazide (BHZ) results in biotinylation of LOXL2-catalyzed peptidyl lysines.
