Search results for "hydroxylation"

Identification and expression of the 11β‐steroid hydroxylase from Cochliobolus lunatus in Corynebacterium glutamicum

2019

Hydroxylation of steroids has acquired special relevance for the pharmaceutical industries. Particularly, the 11β-hydroxylation of steroids is a reaction of biotechnological importance currently carried out at industrial scale by the fungus Cochliobolus lunatus. In this work, we have identified the genes encoding the cytochrome CYP103168 and the reductase CPR64795 of C. lunatus responsible for the 11β-hydroxylase activity in this fungus, which is the key step for the preparative synthesis of cortisol in industry. A recombinant Corynebacterium glutamicum strain harbouring a plasmid expressing both genes forming a synthetic bacterial operon was able to 11β-hydroxylate several steroids as subs…

Stereoselective synthesis and application of tridentate aminodiols derived from (+)-pulegone

2016

Abstract A library of tridentate aminodiols, derived from naturally occurring (R)-(+)-pulegone, was synthesized and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. The reduction of pulegone furnished pulegol, which was transformed into allylic trichloroacetamide via Overman rearrangement of the corresponding trichloroacetimidate. The protected enamine was subjected to dihydroxylation with OsO4/NMO system resulting in a 1:1 mixture of (1R,2R,4R)- and (1S,2S,4R)-aminodiol diastereomers. After the removal of the trichloroacetyl protecting groups, the obtained primary aminodiols were transformed into secondary ones. The regioselectivity of the ring closure of the N-b…

Steroidal saponins from Dioscorea preussii.

2014

Abstract Three new steroidal saponins, named diospreussinosides A–C (1–3), along with two known ones (4, 5) were isolated from rhizomes of Dioscorea preussii. Their structures were elucidated mainly by 1D and 2D NMR spectroscopic analysis and mass spectrometry as (25S)-17α,25-dihydroxyspirost-5-en-3β-yl-O-α- l -rhamnopyranosyl-(1 → 4)-α- l -rhamnopyranosyl-(1 → 4)-β- d -glucopyranoside (1), (25S)-17α,25-dihydroxyspirost-5-en-3β-yl-O-α- l -rhamnopyranosyl-(1 → 4)-α- l -rhamnopyranosyl-(1 → 4)-[α- l -rhamnopyranosyl-(1 → 2)]-β- d -glucopyranoside (2), and (24S,25R)-17α,24,25-trihydroxyspirost-5-en-3β-yl-O-α- l -rhamnopyranosyl-(1 → 4)-α- l -rhamnopyranosyl-(1 → 4)-[α- l -rhamnopyranosyl-(1 → …

�ber die Wirkung von Metyrapon auf den mikrosomalen Arzneimittelabbau

1967

The inhibitor of adrenal steroid-11-β-hydroxylation, Metyrapone (SU 4885), also decreases the rate of drug hydroxylation reactions, both in vitro and in vivo. The follwing oxidative microsomal reactions were studied: O-demethylation of p-nitroanisole, N-demethylation of amidopyrine, and ring hydroxylation of acetanilide. In all three cases Metyrapone inhibits the formation of the reaction products. The inhibitor concentrations required for reduction of the initial reaction rates to one half are 7.5 · 10−4 M, 5 · 10−4m and 20 · 10−4 M, respectively. Steroid C-11-β-hydroxylation is reduced to one half by 2.5 · 10−4 M Metyrapone.

Phenylalanine Hydroxylase Participation in the Synthesis of Serotonin and Pteridines in Drosophila melanogaster

1997

Abstract Phenylalanine hydroxylase is involved in the synthesis of serotonin and pteridines, probably catalysing the hydroxylation of tryptophan and a tetrahydropterin oxidase reaction, respectively. Supplementation of the wild-type Drosophila diet with either L-Phe or L-Trp induced a significant increase in the phenylalanine hydroxylase concentration, while L-Tyr supplementation had no effect. The level of serotonin in adult heads of the PAH-defective mutant Henna recessive-3 was significantly lower than that obtained for the wild-type strain. A 4-fold increase in the concentration of phenylalanine hydroxylase is observed during the pharate adult head development. It occurs in parallel wit…

Regulation of pteridine biosynthesis and aromatic amino acid hydroxylation in Drosophila melanogaster

1989

The relationship between high dietary levels of aromatic amino acid and regulation of pteridines in Drosophila eyes was examined by measuring changes in pool levels of six pterins in the wild type and mutants and amino acid pool levels in flies that carry mutations for pteridine biosynthesis. The effect upon relative viability and developmental times was also analyzed; relative viability was affected by L-phenylalanine, L-tryptophan, and L-tyrosine in decreasing order and the D-amino acids had little or no effect. The changes in concentration of biopterin, dihydrobiopterin, pterin, sepiapterin, drosopterins, and isoxanthopterin showed a characteristic pattern of increased and/or decreased a…

Inhibition of prolyl hydroxylation and procollagen processing in chick-embryo calvaria by a derivative of pyridine-2,4-dicarboxylate. Characterizatio…

1991

The biochemical and morphological consequences of procollagen prolyl 4-hydroxylase inhibition by pyridine-2,4-dicarboxylic acid (2,4-PDCA) and its diethyl ester (diethyl-2,4-PDC) were studied in chick-embryo calvaria, which predominantly synthesize type I collagen. Half-maximal inhibition of tissue hydroxyproline formation required 650 microM-2,4-PDCA, whereas the Ki with respect to chicken prolyl 4-hydroxylase in vitro was 2 microM. In contrast, half-maximal inhibition was caused by 10 microM-diethyl-2,4-PDC in the intact calvaria, although chicken prolyl 4-hydroxylase in vitro was not inhibited even at 1 mM. The collagenous material produced in the presence of diethyl-2,4-PDC showed an al…

Column switching and high-performance liquid chromatography in the analysis of amitriptyline, nortriptyline and hydroxylated metabolites in human pla…

1992

A column-switching system for the direct injection of plasma or serum samples, followed by isocratic high-performance liquid chromatography and ultraviolet detection, is described for the simultaneous quantitation of the tricyclic antidepressant amitriptyline, its demethylated metabolite nortriptyline and the E- and Z-isomers of 10-hydroxyamitriptyline and 10-hydroxynortriptyline. The method included adsorption of amitriptyline and metabolites on a reversed-phase C8 clean-up column (10 microns; 20 mm x 4.6 mm I.D.), washing of unwanted material to waste and, after on-line column-switching, separation on a cyanopropyl analytical column (5 microns; 250 mm x 4.6 mm I.D.). The compounds of inte…

Reversible inhibition of C1Q release from guinea pig macrophages by 2,2'-dipyridyl: Evidence for a posttranslational hydroxylation step in the biosyn…

1978

Selective oxidation of phenol and benzoic acid in water via home-prepared TiO2 photocatalysts: Distribution of hydroxylation products

2012

Abstract The hydroxylation of phenol (a substrate containing an electron donor group) and of benzoic acid (a substrate containing an electron withdrawing group) has been carried out by the photocatalytic method in aqueous suspensions containing commercial or home prepared TiO2 samples. The aim of the work was to study the distribution of hydroxylation products when different photocatalysts were used and to correlate the selectivity to some physico-chemical features of the powders. The samples were characterized by X-ray diffraction, thermogravimetry, determination of crystalline phase percentage, specific surface area and zero charge point. The photoreactivity results indicate that the prod…