A maleimide-reactive reagent used to functionalize peptides or proteins with an alkyne group. The alkyne group can then be further modified via Sonogashira coupling reactions.1
Sonogashira, K.; Tohda, Y.; Haghiara, N. A convenient synthesis of acetylenes: catalytic substitutions of acetylenic hydrogen with bromoalkenes, iodoarenes, and bromopyridines. Tetrahedron Lett.,1975 (16) 4467-4470.