Contributions of conserved serine and tyrosine residues to catalysis, ligand binding, and cofactor processing in the active site of tyrosine ammonia lyase

Tyrosine ammonia lyase (TAL) catalyzes the conversion of l-tyrosine to p-coumaric acid using a 3,5-dihydro-5-methylidene-4H-imidazole-4-one (MIO) prosthetic group. Using a combination of site-directed mutagenesis, kinetic analysis, mass spectrometry, and fluorescence spectroscopy, the role of conserved active site residues are examined.