نتایج جستجو برای: hydroxylase
تعداد نتایج: 16682 فیلتر نتایج به سال:
The rate-limiting step in bile acid biosynthesis is catalyzed by the microsomal cytochrome P-450 cholesterol 7 alpha-hydroxylase (7 alpha-hydroxylase). The expression of this enzyme is subject to feedback regulation by sterols and is thought to be coordinately regulated with enzymes in the cholesterol supply pathways, including the low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl...
Inhibition of lysyl hydroxylase and prolyl 3-hydroxylase was studied with 23 selected aromatic and aliphatic structural analogues of 2-oxoglutarate and the results were compared with those previously reported for prolyl 4-hydroxylase. All the compounds inhibited the hydroxylases competitively with respect to 2-oxoglutarate and noncompetitively with respect to Fe2+ and the peptide substrate. The...
in this study the clinical and epidemiological characteristics of congenital adrenal hyperplasia were evaluated prospectively in 47 patients admitted in imam reza hospital in mashhad during a 4 year period. 21-hydroxylase deficiency was present in 42 patients (89.3%), the simple virilizing form in 6 and the salt-losing form in 36 of them. 11b hydroxylase deficiency was present in 5 patients (10...
Tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, is subject to regulation by a variety of agents. Previous workers have found that cyclic AMP-dependent protein kinase and calcium-stimulated protein kinases activate tyrosine hydroxylase. We wanted to determine whether cyclic GMP might also be involved in the regulation of tyrosine hydroxylase activity. We found that ...
Tyrosine hydroxylase activity is reversibly controlled by the actions of several protein kinases. Previous studies showed that, following phosphorylation by protein kinase A, physiological concentrations of ascorbate irreversibly inactivate tyrosine hydroxylase. Several studies were performed to establish the mechanism of inactivation. We found that inactivation occurred under oxygen-free condi...
It is known that hepatic levels of reduced glutathione correlate with the activity of the liver-specific enzyme cholesterol-7alpha-hydroxylase. We examined the possibility that sulfhydryl reducing agents activate transcription of cholesterol 7alpha-hydroxylase. Adding dithiothreitol (DTT, 1 mM) and dexamethasone to L35 hepatoma cells increased the content of 7alpha-hydroxylase mRNA 3-fold above...
The present paper describes tyrosine hydroxylase-like immunoreactivity in the ciliary ganglion of monkey (Macaca fascicularis) and cat. Under the light microscope, in the monkey, about 7.6% of neurons were observed to be intensely stained, 27.7% moderately stained and 32.5% lightly stained. In the cat, 1.2% of neurons were intensely stained, 5.4% moderately stained and 10.1% lightly stained. Ul...
Antibodies to pure lysyl hydroxylase from whole chick embryos were prepared in rabbits and used for immunological characterization of this enzyme of collagen biosynthesis. In double immunodiffusion a single precipitation line was seen between the antiserum and crude or pure chick-embryo lysyl hydroxylase. The antiserum effectively inhibited chick-embryo lysyl hydroxylase activity, whether measu...
The enzyme tyrosine hydroxylase catalyzes the first step in the biosynthesis of dopamine, norepinephrine, and epinephrine. Tyrosine hydroxylase is a substrate for cyclic AMP-dependent protein kinase as well as other protein kinases. We determined the Km and Vmax of rat pheochromocytoma tyrosine hydroxylase for cyclic AMP-dependent protein kinase and obtained values of 136 microM and 7.1 mumol/m...
Tyrosine hydroxylase deficiency is an autosomal recessive disorder resulting from cerebral catecholamine deficiency. Tyrosine hydroxylase deficiency has been reported in fewer than 40 patients worldwide. To recapitulate all available evidence on clinical phenotypes and rational diagnostic and therapeutic approaches for this devastating, but treatable, neurometabolic disorder, we studied 36 pati...
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