Paul Fitzpatrick, Ph.D.

Img 8202


Dr. Paul Fitzpatrick's lab studies the regulatory and catalytic properties of the aromatic amino acid hydroxylases tyrosine hydroxylase (TyrH) and phenylalanine hydroxylase (PheH). TyrH, the key enzyme in the biosynthesis of the catecholamine neurotransmitters, utilizes a non-heme iron atom to catalyze oxygen activation and addition. The enzyme is regulated by phosphorylation and feedback inhibition. 

PheH, an allosteric enzyme deficient in phenylketonuria, has a similar catalytic mechanism and a similar structure, but differs in its regulatory properties. We utilize a range of biochemical and biophysical techniques, from single turnover kinetics to NMR spectroscopy.

Selected Publications

Wang S, Lasagna M, Daubner SC, Reinhart GD, Fitzpatrick PF. Fluorescence spectroscopy as a probe of the effect of phosphorylation at serine 40 of tyrosine hydroxylase on the conformation of its regulatory domain. Biochemistry. 2011 Mar 29;50(12):2364-70.

Fitzpatrick PF. Allosteric regulation of phenylalanine hydroxylase. Arch Biochem Biophys. 2012 Mar 15;519(2):194-201.

Daubner SC, Avila A, Bailey JO, Barrera D, Bermudez JY, Giles DH, Khan CA, Shaheen N, Thompson JW, Vasquez J, Oxley SP, Fitzpatrick PF. Mutagenesis of a specificity-determining residue in tyrosine hydroxylase establishes that the enzyme is a robust phenylalanine hydroxylase but a fragile tyrosine hydroxylase. Biochemistry. 2013 Feb 26;52(8):1446-55.

Li J, Fitzpatrick PF. Regulation of phenylalanine hydroxylase: conformational changes upon phosphorylation detected by H/D exchange and mass spectrometry. Arch Biochem Biophys. 2013 Jul 15;535(2):115-9.

Zhang S, Huang T, Ilangovan U, Hinck AP, Fitzpatrick PF. The Solution Structure of the Regulatory Domain of Tyrosine Hydroxylase. J Mol Biol. 2013 Dec 17.


Biochemistry and Structural Biology


Ph.D., Biological Chemistry, University of Michigan, 1981



Phone: (210) 567-8264

Research Profile
More Info...

Graduate Students

Crystal Olivas Khan