Role of tryptophan hydroxylase phe313 in determining substrate specificity.
The active site residue phenylalanine 313 is conserved in the sequences of all known tryptophan hydroxylases. The tryptophan hydroxylase F313W mutant protein no longer shows a preference for tryptophan over phenylalanine as a substrate, consistent with a role of this residue in substrate specificity. A tryptophan residue occupies the homologous position in tyrosine hydroxylase. The tyrosine hydroxylase W372F mutant enzyme does not show an increased preference for tryptophan over tyrosine or phenylalanine, so that this residue cannot be considered the dominant factor in substrate specificity in this family of enzymes.
Daubner
S Colette
SC
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
Moran
Graham R
GR
Fitzpatrick
Paul F
PF
D000818:Animals; D001665:Binding Sites; D007700:Kinetics; D010649:Phenylalanine / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D013379:Substrate Specificity; D014365:Tryptophan Hydroxylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D010649:Phenylalanine; D014446:Tyrosine 3-Monooxygenase; D014365:Tryptophan Hydroxylase