Deamidations in Recombinant Human Phenylalanine Hydroxylase

Deamidations in recombinant human phenylalanine hydroxylase. Identification of labile asparagine residues and functional characterization of Asn --> Asp mutant forms.

Recombinant human phenylalanine hydroxylase (hPAH) expressed in Escherichia coli for 24 h at 28 degrees C has been found by two-dimensional electrophoresis to exist as a mixture of four to five molecular forms as a result of nonenzymatic deamidation of labile Asn residues. The multiple deamidations alter the functional properties of the enzyme including its affinity for l-phenylalanine and tetr...

Mouse phenylalanine hydroxylase. Homology and divergence from human phenylalanine hydroxylase.

The laboratory mouse represents an important model for the study of phenylalanine metabolism and the pathochemistry of phenylketonuria, yet mouse phenylalanine hydroxylase (PAH) has not been extensively studied. We report the cloning and sequencing of a mouse PAH cDNA, the expression of enzymic activity from the mouse PAH cDNA clone and the identification of mouse PAH and human PAH by two-dimen...

Biochemical characterization of recombinant human phenylalanine hydroxylase produced in Escherichia coli.

A full-length human phenylalanine hydroxylase cDNA has been recombined with a prokaryotic expression vector and introduced into Escherichia coli. Transformed bacteria express phenylalanine hydroxylase immunoreactive protein and pterin-dependent conversion of phenylalanine to tyrosine. Recombinant human phenylalanine hydroxylase produced in E. coli has been partially purified, and biochemical st...

Phenylalanine Hydroxylase, Tyrosine Hydroxylase, and Tryptophan Hydroxylase

Recombinant human phenylalanine hydroxylase is a substrate for the ubiquitin-conjugating enzyme system.

Mammalian phenylalanine hydroxylase (PAH) catalyses the conversion of L-phenylalanine to L-tyrosine in the presence of dioxygen and tetrahydrobiopterin; it is a highly regulated enzyme. Little is known about the rates of synthesis and degradation of PAH in vivo. The enzyme has been reported to have a half-life of approx. 2 days in rat liver and 7-8 h in rat hepatoma cells, but the mechanism of ...