SEARCH Articles Figures Tables Proton histidine cycle Tyrosine, proton transfer to histidine R)- -Umbelactone, isolation from Tyrosine, proton transfer to histidine Ungeremine Tyrosine, proton transfer to histidine enzymes Tyrosine, proton transfer to histidine plants Tyrosine, proton transfer to histidine radicals, in photosystem Tyrosine, proton transfer to histidine synthesis