Phenylketonuria (PKU) is one of the most common metabolic inborn diseases caused by mutations in the phenylalanine hydroxylase (PAH) gene. This gene is linked to a variable number of tandem repeats (VNTR) region which is a polymorphic marker that facilitates the implementation of prenatal diagnosis and carrier screening. In this study, VNTR with 13 repeats that has not been reported previously ...

Tyrosine hydroxylase, the rate limiting enzyme in the biosynthesis of catecholamine, is a tetramer composed of four subunits of the same molecular mass. A full length cDNA clone encoding tyrosine hydroxylase has been inserted into the SP6 expression system. Translation of the corresponding RNA in Xenopus oocyte results in enzymatic activity, demonstrating that a single gene contains all the nec...

With the use of heterogenic stock (HS) mice, more than g-fold differences in hepatic microsomal 3-methylcholanthrene-inducible aryl hydrocarbon (benzo[alpyrene) hydroxylase (EC 1.14.14.2) activity and at least 4-fold differences in 3-methylcholanthrene-inducible acetanilide 4-hydroxylase activity were found. These data strongly suggest independent genetic control of two inducible cytochrome P-4...

Exposure of rats to nickel carbonyl by inhalation (0.2 mg Ni/liter of air/15 min) or intravenous injection (2 mg Ni/100 gm) was found to inhibit the induction of benzpyrene hydroxylase in lung and liver. Phenothiazine induction and fluorometric measurements of benzpyrene hydroxylase were performed by the methods of Wattenberg and co-workers (31, 32). Benzpyrene hydroxylase activities in lungs a...

OBJECTIVE This study sought to examine corticosteroidogenic enzyme activities in normo- and hyperandrogenic polycystic ovary syndrome (PCOS) patients. SUBJECTS AND METHODS This cohort study included 81 patients with biochemical hyperandrogenism and 41 patients with normal androgen levels. Enzyme activities were assessed according to the serum steroid product/precursor ratios at baseline and a...

The action of prostaglandin E1 on tyrosine hydroxylase activity in adrenal slices of guinea pig was studied. The activity of tyrosine hydroxylase and was decreased by the incubation of adrenal slices with prostaglandin E1 at concentrations beyond 2 mug per ml for 2 hours. The activity of tyrosine hydroxylase was stimulated by dibutyryl adenosine 3',5'-monophosphate in slices of guinea pig adren...

The rate of release of deuterons into the body water from 2,3,4,5,6-pentadeutero-L-phenylalanine has been shown to be a valid measure of the activity of the phenylalanine hydroxylase system in vivo. At a dose of 0.5 g/kg, the rate of release of deuterons is linear for 60 to 90 min. Male rats, which had previously been shown to have 22 to 25% more phenylalanine hydroxylase activity in liver extr...

27-Hydroxycholesterol (27OH) is the major oxysterol in human atherosclerotic lesions, followed by 7-ketocholesterol (7K). Whereas 7K probably originates nonenzymically, 27OH arises by the action of sterol 27-hydroxylase, a cytochrome P450 enzyme expressed at particularly high levels in the macrophage and proposed to represent an important pathway by which macrophages eliminate excess cholestero...

2-Hydroxylation is one of the major metabolic pathways of estrogens and is believed to be catalyzed by a form of cytochrome P450. Recently it has been reported that estrogen 2-hydroxylase activity in human placenta is catalyzed by aromatase. Some investigators suggested the effect of catechol estrogen on human placental steroidogenesis which may be related to pregnancy-induced hypertension (PIH...

A method was developed to study the unsupplemented phenylalanine hydroxylase system in rat liver slices. All of the components of the system--tetrahydrobiopterin, dihydropteridine reductase, and the hydroxylase itself--are present under conditions which should be representative of the actual physiological state of the animal. The properties of the system in liver slices have been compared to th...