Imidazole group is 1,3 diazolane, and its English name is ImidazoleNitrogen atomGet rid of thathydrogen atomThe rest isimidazoleThe part left after dropping a hydrogen atom directly connected to the nitrogen atom.Various imidazolyl groups in histidine can occurchemical reaction, can be compared withATPPhosphoylation reaction occurs to formphosphoric acidhistidineTo activate the enzyme.