phenylalanyl-trna synthetase from the archaebacterium methanosarcina barkeri activates a number of phenylalanine analogues ( methionine , p-fluorophenylalanine , beta-phenylserine , beta-thien-2-ylalanine , 2-amino-4-methylhex-4-enoic acid and ochratoxin a ) in the absence of trna , as demonstrated by km and kcat of the atp/ppi exchange reaction .
C0031453
phenylalanine
C0030137
p-fluorophenylalanine