Vitamin D is an important regulator of mineral homeostasis and bone metabolism. 1Alpha-hydroxylation of 25-(OH)D3 to form the bioactive vitamin D hormone, 1alpha,25-(OH)2D3, is classically considered to take place in the kidney. However, 1alpha-hydroxylase has been reported at extrarenal sites. Whether bone is a 1alpha,25-(OH)2D3 synthesizing tissue is not univocal. The aim of this study was to...

Cholesterol 24-hydroxylase is a cytochrome P450 (CYP46A1) that is selectively expressed in the brain and is responsible for the majority of cholesterol turnover in the central nervous system. Mice deficient in 24-hydroxylase exhibit impaired learning and defective hippocampal long-term potentiation, suggesting that the metabolism of cholesterol by this enzyme is required for learning and memory...

Dopaminergic lesions result in the acute loss of striatal dopamine content, the loss of tyrosine hydroxylase-immunoreactive fibers, upregulation of preproenkephalin mRNA expression, and compensatory changes in the synthesis and metabolism of dopamine. Despite the severe loss of fine tyrosine hydroxylase-immunoreactive fibers, larger fibers persist. We found that some tyrosine hydroxylase fiber ...

Tryptophan hydroxylase, the initial and rate-limiting enzyme in serotonin biosynthesis, is inactivated by peroxynitrite in a concentration-dependent manner. This effect is prevented by molecules that react directly with peroxynitrite such as dithiothreitol, cysteine, glutathione, methionine, tryptophan, and uric acid but not by scavengers of superoxide (superoxide dismutase), hydroxyl radical (...

The interaction between the hydroxylase component of methane monooxygenase (MMO) from Meth~ococcus capsu/atus (Bath), the coupling protein of the MMO enqme system (component B) and substrate has been investigated by using Fe K~dge x-ray absorption spectros-copy (MS). Fe K-edge extended x-ray abso~tion fine stmcture (EXAFS) studies of the semimet form of the hydroxylase in the presence of the co...

Alternative Names Adrenal Hyperplasia III 21-@Hydroxylase Deficiency CYP21 Deficiency Congenital Adrenal Hyperplasia 1 CAH1 Cytochrome P450, Subfamily XXIA, Polypeptide 2 CYP21A2 Cytochrome P450, Subfamily XXI CYP21 Steroid Cytochrome P450 21-Hydroxylase P450c21 21-@Hydroxylase B, Included CYP21B CA21H Cytochrome P450, Subfamily XXIA, Polypeptide 1 Pseudogene CYP21A1P CYP21P CYP21A Hyperandroge...

The hydroxylase cofactor, tetrahydrobiopterin, and its biosynthetic system are localized in dopaminergic nerve terminals in the striatum. This conclusion is based on the nearly equivalent loss of tyrosine hydroxylase and tetrahydrobiopterin and its initial biosynthetic enzyme, guanosine triphosphate cyclohydrolase, after injection of 6-hydroxydopamine into the substantia nigra. The role of the ...

PURPOSE Vitamin D seems to exert a protective effect against common cancers, although this does not correlate with circulating levels of active 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], indicating a more localized activation of vitamin D. The aim of this study was to investigate the significance of this in breast cancer. EXPERIMENTAL DESIGN Quantitative reverse transcription-PCR analysis of mRN...

The phosphorylation of human phenylalanine hydroxylase by cyclic AMP-dependent protein kinase was studied using recombinant enzyme expressed as a fusion protein in the pMAL system of Escherichia coli. Using the target sequence of the restriction protease enterokinase (Asp4-Lys) as the linker peptide, 100% full-length human phenylalanine hydroxylase was obtained on protease cleavage. The fusion ...