scholarly journals 3-Hydroxy steroid dehydrogenase activities of cortisone reductase

1973 ◽  
Vol 135 (4) ◽  
pp. 881-888 ◽  
Author(s):  
William Gibb ◽  
Jonathan Jeffery
Keyword(s):  
Binding Site ◽  
Substrate Molecule ◽  
Ring Junction ◽  
Nad Oxidoreductase ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

The behaviour of various C19 and C18 steroids as substrates for crystalline preparations of cortisone reductase (EC 1.1.1.53) is described. 3α(Axial,3R)-, 3α(equatorial,3R)- and 3β(axial,3S)-hydroxy steroid–NAD oxidoreductase activities are demonstrated. Four pairs of the substrates differed only in the shape of the a/b ring junction, three pairs differed only in substitution at C-10, and four pairs differed only in substitution in ring d. The shape of the substrate molecule and certain substituents (e.g. 10β-methyl, 17β-hydroxy, 16-oxo or 17-oxo) altered substrate behaviour, but steroids differing considerably in shape nevertheless acted as substrates, suggesting the possibility of a large or flexible binding site. Km values varied about 10-fold, many being approx. 140μm. Vmax. values covered a greater range (about 200-fold) and the good substrates had high Vmax. values rather than low Km values.

scholarly journals Competition of two substrates for a single enzyme. A simple kinetic theorem exemplified by a hydroxy steroid dehydrogenase reaction

1969 ◽  
Vol 112 (3) ◽  
pp. 331-334 ◽  
Author(s):  
T. Pocklington ◽  
J. Jeffery
Keyword(s):  
Initial Rate ◽  
Maximum Velocity ◽  
Total Rate ◽  
Dehydrogenase Reaction ◽  
Rate Of Reaction ◽  
Nad Oxidoreductase ◽  
Lower Maximum ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase ◽  
Single Enzyme

1. If two compounds are substrates for a single enzyme, and do not form any ternary complex with the enzyme or combine directly with each other, then the total initial rate of reaction for a mixture of the two compounds may be greater than the rate for either compound alone, or may lie between the rates for the compounds alone. It is the concentration of the compound with the higher maximum velocity that determines which applies, and there is one concentration of the compound of higher maximum velocity at which the total rate of reaction is independent of the presence or absence of the substrate of lower maximum velocity. The values concerned are derived. 2. An example is given of 5α-androstan-3-one and 5α-androstane-3,16-dione as substrates competing for a hydroxy steroid–NAD oxidoreductase (EC 1.1.1.53).

ÜBER DEN ENZYMATISCHEN ABBAU VON D,L-3-METHOXY-4-HYDROXY-MANDELSÄURE ZU VANILLINSÄURE

1969 ◽  
Vol 61 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Wilhelm Dirscherl ◽  
Betty Brisse
Keyword(s):  
Enzymatic Activity ◽  
Pseudomonas Fluorescens ◽  
Rat Liver ◽  
Mandelic Acid ◽  
Glyoxylic Acid ◽  
Type Iv ◽  
Quantitative Measurements ◽  
Nad Oxidoreductase ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

ABSTRACT The dehydrogenation of DL-3-methoxy-4-hydroxy-mandelic acid to 3-methoxy-4-hydroxyphenyl-glyoxylic acid by fractions of the rat liver, 20β-hydroxy-steroid-dehydrogenase (1. 1. 1.53, C = 20-dihydrocortisone: NAD oxidoreductase) and cells of pseudomonas fluorescens Type IV, as well as fractions obtained of this strain, was proved by paper chromatography of the incubation extracts. Quantitative measurements and kinetic research was only possible with cells of pseudomonas fluorescens and fractions obtained of them. The enzymatic activity is bound to the particles of the pseudomonas cells and the microsomes of the rat liver. Until now it was only possible to get just a small amount into solution.

A metabolic stability determination of Tetrahydrothiazolopyridine derivative a selective 11β-hydroxy steroid dehydrogenase type 1 (11β-hsd1) inhibitor

2017 ◽  
Vol 8 (3) ◽  
Author(s):  
MURUGESH KANDASAMY ◽  
MUHAMMED SALIHIN ◽  
MALLIKARJUNA RAO PICHIKA ◽  
SLAVKO KOMARNYTSKY ◽  
THIRUMURUGAN RATHINASABAPATHY
Keyword(s):  
Metabolic Stability ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

DIFFICULTIES IN THE DIAGNOSIS OF THE ADRENOGENITAL SYNDROME IN INFANCY

PEDIATRICS ◽  
1972 ◽  
Vol 49 (2) ◽  
pp. 198-205
Author(s):  
C. H. Shackleton ◽  
F. L. Mitchell ◽  
J. W. Farquhar
Keyword(s):  
Hydroxylase Deficiency ◽  
Adrenogenital Syndrome ◽  
Steroid Excretion ◽  
21 Hydroxylase Deficiency ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

Pregnanetriol was not excreted by an infant (7 days old) who was later shown to have a defect in steroid 21-hydroxylase. However, the excretion of this compound increased during the following days (1.2 mg on the thirteenth day of life). A high excretion of 3β-hydroxy-Δ steroids was the most noticeable abnormality in steroid excretion noted on the seventh day of life (e.g., 3β, 16α-dihydroxy-5-pregnen-20-one, 15 mg; 3β, 21-dihydroxy-5-pregnen-20-one, 1.4 mg and 3β, 16α-dihydroxy-5-androsten-17-one, 7.4 mg). This high 3β-hydroxy-Δ steroid excretion results in difficulties in distinguishing a defect in 3β-hydroxy steroid dehydrogenase from a 21-hydroxylase deficiency. At the age of 14 months the principal steroids excreted were those predominant in other cases of 21-hydroxylase deficiency, viz. pregnanetriol and 5β-pregnane-3α, 17α, 20α-triol-11-one (11-oxo-pregnanetriol).

Bestimmung des Molekulargewichtes der 20-β-Hydroxy-steroid-dehydrogenase

1962 ◽  
Vol 17 (7) ◽  
pp. 432-436 ◽  
Author(s):  
Matatiahu Gehatia
Keyword(s):  
Molecular Weight ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Specific Volume ◽  
Sedimentation Coefficient ◽  
Partial Specific Volume ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

The enzyme 20-β-Hydroxy-steroid-dehydrogenase obtained from the culture of Streptomyces hydrogenans and dissolved in 0.05 M Tris puffer, pH 7.3, has been investigated by means of a ultracentrifuge at 20 °C. The sedimentation- as well as the diffusion-coefficients obtained from various solutions at different concentrations were extrapolated to the concentration c = 0. The resulting zero-value for the sedimentation coefficient is s0 = 6.64 s and for the diffusion coefficient is D0 = 5.51 × 10-7 cm2/sec. Supposing the partial specific volume of the enzyme under consideration analogously to other similar proteins is V+=0.749 ml/g, the molecular weight has been estimated as M = 118 400.

scholarly journals Mechanistic and stereochemical studies on 3-oxo steroid Δ4-Δ5-isomerase from human placenta

1980 ◽  
Vol 185 (2) ◽  
pp. 411-421 ◽  
Author(s):  
M Akhtar ◽  
M Calder ◽  
T Smith ◽  
J N Wright
Keyword(s):  
Double Bond ◽  
Hydrogen Atom ◽  
Human Placenta ◽  
Microsomal Fraction ◽  
Isomerization Reaction ◽  
Acidic Group ◽  
Incoming Proton ◽  
Membrane Bound ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

The mechanism of isomerization of delta 5-3-ox steroids to delta 4-3-oxo steroids was examined by using the membrane-bound 3-oxo steroid delta 4-delta 5-isomerase (EC 5.3.3.1) and the 3 beta-hydroxy steroid dehydrogenase present in the microsomal fraction obtained from full-term human placenta. (1) Methods for the preparation of androst-5-ene-3 beta, 17 beta-diol specifically labelled at the 4 alpha-, 4 beta- or 6-positions are described. (2) Incubations with androst-5-ene-3 beta, 17 beta-diol stereospecifically 3H-labelled either in the 4 alpha- or 4 beta-position showed that the isomerization reaction occurs via a stereospecific elimination of the 4 beta hydrogen atom. In addition, the complete retention of 3H in the delta 4-3-oxo steroids obtained from [4 alpha-3H]androst-5-ene-3 beta, 17 beta-diol indicates that the non-enzymic contribution to these experiments was negligible. (3) To study the stereochemistry of the insertion of the incoming proton at C-6, the [6-3H]androst-4-ene-3, 17-dione obtained from the oxidation isomerization of [6-3H]androst-5-ene-3 beta, 17 beta-diol was enzymically hydroxylated in the 6 beta-position by the fungus Rhizopls stolonifer. Retention of 3H in the 6 alpha-position of the isolated 6 beta-hydroxyandrost-4-ene-3, 17-dione indicates that in the isomerase-catalysed migration of the C(5) = C(6) double bond, the incoming proton from the acidic group on the enzyme must enter C-6 from the beta-face, forcing the existing 3H into the 6 alpha-position.

Steroid characteristics of mineralocorticoid adrenocortical hypertension

1991 ◽  
Vol 37 (10) ◽  
pp. 1843-1848 ◽  
Author(s):  
E G Biglieri ◽  
C E Kater
Keyword(s):  
Plasma Renin ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Hydroxylase Deficiency ◽  
Aldosterone Production ◽  
Apparent Mineralocorticoid Excess ◽  
Tomography Scan ◽  
Apparent Mineralocorticoid Excess Syndrome ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

Abstract Adrenocortical causes of hypertension are established by examining the mineralocorticoid hormones produced in the zona glomerulosa and zona fasciculata. In the zona glomerulosa, aldosterone excess leads to hypertension, hypokalemia, and suppressed plasma renin activity, with increased concentrations of urinary aldosterone (either as the 18-glucuronide or free aldosterone) as an index of its production. Identifying a tumor by computed tomography scan verifies the diagnosis of a correctable lesion. If no tumor is found, several maneuvers are used to identify primary adrenal hyperplasia, a disorder with autonomous aldosterone production, for which reduction of adrenal mass is curative. The zona fasciculata has two major pathways: the 17-deoxy pathway, where deoxycorticosterone (DOC) and corticosterone are the significant steroids, and the 17-hydroxy pathway, which leads to cortisol production. Tumors of the 17-deoxy pathway, DOC-producing adenomas, have increased concentrations of DOC and its precursor steroids, normal concentrations of cortisol, and suppression of aldosterone production secondary to suppression of the renin system. Two enzymatic defects in the zona fasciculata, 11 beta- and 17 alpha-hydroxylase deficiency, can be first readily identified by the virilization in the former, hypogonadal features in the latter. Steroid patterns are diagnostic. DOC is produced in excess in both deficiencies and is the cause of the hypertension. Deficient or impaired 11 beta-hydroxy steroid dehydrogenase in the apparent mineralocorticoid excess syndrome or after licorice ingestion retards the conversion of cortisol to inactive cortisone in the kidney, leading to mineralocorticoid hypertension; this leads to suppression of the renin system and subsequently of aldosterone.

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