Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.3 (HSD)
3,464 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

3beta-hydroxysteroid dehydrogenase and NADH-ferricyanide reductase activities were localized at the ultrastructural level in amphibian interrenal (adrenocortical) cells previously fixed in a mixture of formaldehyde and glutaraldehyde. Potassium ferricyanide was used as an electron acceptor. Copper ferrocyanide deposits resulting from 3beta-HSD activity were seen in close association with the external faces of the membranes of the smooth endoplasmic reticulum. Very rare grains of precipitate appeared in mitochondrial cristae. The addition of phenazine methosulfate to the incubation medium had no effect on these localizations. The interrenal cells showed also a strong NADH-ferricyanide reductase activity. The copper ferrocyanide grains were abundant in the mitochondrial cristae and in the hyaloplasm, where they were not preferentially associated with the smooth endoplasmic reticulum.
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PMID:Electron microscopic localization of 3beta-hydroxysteroid dehydrogenase and NADH-ferricyanide reductase activities in amphibian interrenal cells. 30 25

Results on the kinetics of 7 alpha-hydroxysteroid dehydrogenase 7 alpha-HSDH showed that this enzyme could oxidize all bile acids having an -OH group at the C-7 position. Lineweaver-Burk plots showed Michaelis constant (Km) values of 0.83 and 0.12 mM for cholic acid and chenodeoxycholic acid, respectively. The effect of enzyme concentration on the reaction velocity showed a constant increase in the enzyme activity with increase in enzyme-protein concentration. 7 alpha-HSDH was activated by Na+, K+, Ca2+, and Mn2+ ions and by reducing agents having a thiol group (dithiothreitol, 2-mercaptoethanol). Co2+, Hg2+, Fe3+, Mg2+, Zn2+, Ba2+, and Cu2+ ions, chelating agents (potassium oxalate, heparin, EDTA) oxidizing agents (sodium perchlorate, sodium periodate, sodium persulphate), and detergents (Tween 20, Tween 40, Tween 80, Triton X-100, sodium lauryl sulphate) were inhibitory to 7 alpha-HSDH activity.
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PMID:Kinetic properties of 7 alpha-hydroxysteroid dehydrogenase from Escherichia coli 080. 269 65

The 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSDH) is a key enzyme in human fetal and maternal progesterone metabolism. In this paper, the cytoplasmic 20 alpha-HSDH of human term placenta is partially characterized in vitro. A 14-fold concentration of the 20 alpha-HSDH was prepared by ultracentrifugation and ammonium sulfate precipitation. The apparent Km values for the substrates progesterone (Km: 4.8 x 10(-5) M) and 20 alpha-DHP (Km: 6.2 x 10(-5) M) and for the cofactors NADPH (Km: 1.9 x 10(-4)) and NADH (Km: 2.6 x 10(-4)) were determined. The temperature optimum for the oxidation of 20 alpha-DHP is 40--50 degrees C. The pH optimum for the reduction of progesterone was found to be pH 6.2 and for the oxidation of 20 alpha-DHP pH 6.5. The addition of glycerol (3 M) to the incubation medium inhibited the conversion rate of 20 alpha-HSDH by 70%. No influence of EDTA could be found. Various bivalent metal ions (1--100 mM) showed a dose-dependent inhibition of 20 alpha-HSDH; a complete inhibition was achieved at 100 mM: Cu2+, Zn2+, Cd2+, Fe2+ and Ni2+.
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PMID:Partial characterization of the cytoplasmic 20 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.149) of the human placenta at term. 695 67

A partial characterization of human term placental 3 beta-HSDH in mitochondria is reported. Apparent KM of pregnenolone: 70 nM. A dose-dependent stimulation of 3 beta-HSDH by NAD+ or NADP+ was observed in the range from 10(-6) to 10(-3) M (KM value of NAD+: 20 microM). At equimolar concentrations NAD+ is more than 10-fold as effective a cofactor of the 3 beta-HSDH than NADP+. pH optimum: 9.5 (glycine-NaOH buffer). Temperature optimum 40-45 degrees C. A rapid loss of 3 beta-HSDH activity was found after preincubation of the enzyme at 37 degrees C after 30 min; less than 50% of initial enzyme activity is present. No inhibition was obtained by Mg2+, Ca2+ Sr2+ and Ba2+ (1-100 mM). A strong inhibition was achieved with 1 mM Zn2+, Cd2+, Cu2+ and 10 mM and 100 mM Fe2+, Mn2+, Co2+ and Ni2+.
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PMID:Partial characterization of placental 3 beta-hydroxysteroid dehydrogenase (EC 1.1.1.145), delta 4-5isomerase (EC 5.3.3.1) in human term placental mitochondria. 695 97

NADPH-dependent 5 alpha-dihydrotestosterone 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) was purified to apparent homogeneity from mature pig testicular cytosol. The purified enzyme catalyzed the conversion of 5 alpha-dihydrotestosterone (5 alpha-DHT) to 5 alpha-androstane-3 beta, 17 beta-diol. The molecular weight was estimated to be 31 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 28 kDa by gel filtration chromatography, indicating that the native 3 beta-HSD is a monomer. The isoelectric point of the purified enzyme was 5.8 as determined by chromatofocusing. The purified enzyme reduced not only 5 alpha-DHT but also 5 beta-DHT, 5 alpha(or 5 beta)-androstanedione, 5 alpha(or 5 beta)-dihydroprogesterone, prostaglandin E1, 13,14-dihydro-15-keto-prostaglandin F2 alpha, glyceladehyde, xylose and glucuronic acid. Moreover, the enzyme reduced other carbonyl compounds including aromatic aldehydes, aromatic ketones and quinones such as 4-nitrobenzaldehyde, 4-benzoylpyridine, phenylglyoxal, cyclohexanone and 9,10-phenanthrenequinone at high rates when compared with steroids, prostaglandins and sugars. The purified enzyme was inhibited by AgNO3, SH-reagent, disulfiram, hexesterol, stilbestrol, disulfiram and divalent cations such as Cu2+, Hg2+, Cd2+ and Co2+. Furthermore, the enzymatic properties of the purified enzyme, including catalytic activity, inhibitory effects by various agents and immunological properties, were compared with those of 3 alpha/beta-HSD enzymes from pig testicular cytosol.
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PMID:Purification and characterization of 5 alpha-dihydrotestosterone 3 beta-hydroxysteroid dehydrogenase from mature pig testicular cytosol. 784 33

NADPH-dependent 3 alpha/beta-hydroxysteroid dehydrogenase (3 alpha/beta-HSD) was purified to apparent homogeneity from testicular cytosol of mature pigs. The purified enzyme catalyzes the conversion of 5 alpha-dihydrotestosterone (5 alpha-DHT) to both 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol. The molecular weight of the enzyme was estimated to be 31 kDa by SDS-polyacrylamide gel electrophoresis and 40 kDa by gel filtration chromatography indicating that the native 3 alpha/beta-HSD is a monomer. The isoelectric point of the purified enzyme was found to be 6.2 by density gradient isoelectric focusing and 6.4 by chromatofocusing. The enzyme reduced both 5 alpha- and 5 beta-DHT, 5 alpha- and 5 beta-dihydroprogesterone, 5 alpha- and 5 beta-dihydrocortisol, prostaglandin E2, 13,14-dihydro-15-keto-prostaglandin E2 and 13,14-dihydro-15-keto-prostaglandin F2 alpha. Moreover, the enzyme caused rapid reduction of other carbonyl compounds including aldehydes, ketones and quinones. The rates of reduction of these compounds are fast relative to the rates of reduction of steroids and prostaglandins. The purified enzyme was inhibited by AgNO3, SH-reagent, quercetin, hexesterol, stilbestrol, disulfiram and divalent cation such as Cu2+, Hg2+ and Cd2+. The two enzymes show certain similarities (e.g. molecular weight, cross-reactivity to a common antibody) and certain striking differences (e.g. pI, effects of various inhibitors and greater enzyme activity towards steroids (neonatal form) or prostaglandins (mature form). Reasons are give for suggesting that these enzymes are closely related to carbonyl reductase.
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PMID:Purification and characterization of 3 alpha/beta-hydroxysteroid dehydrogenase from mature porcine testicular cytosol. 814 2

In the biosynthesis of steroid hormones 3beta-hydroxysteroid dehydrogenase (3beta-HSD) is a key enzyme. The present report describes the subcellular localization of the enzyme in the fetal-type Leydig cells, the fibroblast-like precursors of adult-type Leydig cells and in endothelial cells of interstitial capillaries. Histochemical methods for light microscopy and ultracytochemical methods for electron microscopy were used on rat testes of postnatal day 15. 3beta-HSD reactivity was located at subcellular levels by means of the ferricyanide method. A specific, distinct localization of reaction product in the form of copper ferrocyanide precipitates was observed on the membranes of the smooth endoplasmic reticulum not only in the fetal-type Leydig cells and the fibroblast-like precursors of adult-type Leydig cells, but also focally in the endothelial cells of interstitial blood capillaries. Topographically, the 3beta-HSD-positive precursors were most often found in the outer layer of the boundary tissue and surrounding interstitial blood vessels. The capillaries with 3beta-HSD-positive endothelial cells were usually located in the vicinity of 3beta-HSD-positive Leydig cells. For the first time, 3beta-HSD has been located at the subcellular level in precursors of adult-type Leydig cells and focally in capillary endothelial cells associated with them. Due to the close association between 3beta-HSD-positive vascular endothelial cells and Leydig cells a paracrine relationship between the two cell types may be involved in the acute regulation of steroidogenesis by blood-borne luteinizing hormone.
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PMID:Ultracytochemistry of 3beta-hydroxysteroid dehydrogenase in Leydig cell precursors and vascular endothelial cells of the postnatal rat testis. 972 69

Copper chloride treatment adversely affects testicular activity in albino rats. To investigate its antitesticular effects mature (120 days) Wistar strain albino rats were treated intraperitoneally (i.p.) with copper chloride at doses of 1000, 2000 and 3000 micrograms/kg body weight/day for 26 days. Significant reduction of testicular and accessory sex organs (seminal vesicle, ventral prostate) weight, along with inhibition of testicular delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity and reduction in plasma testosterone level, were observed at the doses of 2000 and 3000 micrograms/kg body weight/day. The degree of inhibition in all the parameters were increased with the increase of dosage. But no significant change was observed in the above parameters when the animals were treated with 1000 micrograms/kg body weight/day dose. This suggests that copper produces a suppressive influence on male reproductive activity, mainly on testicular weight and steroidogenesis and accessory sex organ weight in a dose-dependent manner.
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PMID:Antitesticular effect of copper chloride in albino rats. 1065 60

Micronutrients regulate numerous metabolic processes in pregnancy but their possible antioxidant function and contributions of alterations in their metabolism to fetal and maternal morbidity and mortality have received insufficients attention. Serum levels of copper, manganese and zinc were determined in 40 pregnant Nigerian women spread across the three trimesters of pregnancy and compared with those of 25 non-pregnant women of similar demographic and anthropometric characteristics. Serum levels of uric acid were also determined in both groups of women. The mean serum levels of manganese and zinc were significantly lower in the pregnant than in the non-pregnant state (P<0.02, P<0.002), respectively. Unlike manganese and zinc, copper was significantly elevated in the pregnant than in the non-pregnant state. The endogenous anti-oxidant, uric acid, was also significantly reduced in the pregnant than in the non-pregnant state (P<0.001). Copper levels increased progressively in all the three trimesters of pregnancy compared with controls (P<0.001). However, zinc levels declined steadily in all the 3 trimesters, but only the level of the third trimester was significantly different from the non-pregnant state (P<0.05). Unlike zinc, uric acid rose consistently in all the 3 trimesters compared with the non-pregnant state. Manganese and uric acid were significantly more elevated in the third than the first trimester. One way analysis of variance (ANOVA) and multiple comparisons (Tukey HSD) show that the differences in the antioxidant levels can be ascribed mainly to the second and third trimesters. The prevalence of zinc deficiency was 4.0% in the non-pregnant state as compared to 22.5% in the pregnant subjects. The implications of micronutrient deficiencies and associated antioxidant status in pregnancy are discussed. Considering their role in pregnancy, prevention of such deficiencies and attendant oxidative stress may contribute to a reduction in the incidence of fetal and maternal ill-health, and complications of pregnancy. Interventions should be aimed mainly at the second and third trimesters.
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PMID:Serum micronutrient levels, nucleic acid metabolism and antioxidant defences in pregnant Nigerians: implications for fetal and maternal health. 1503 84

Patients with diabetes mellitus are known to develop osteopenia and osteoporosis, apparently as a reduction in the process of bone formation. In order to evaluate whether bone-modulating hormones--estradiol, testosterone, and 1,25(OH)(2)D(3)--have different effects on osteoblasts derived from diabetic and from normal non-diabetic rats, we studied the specific effects of these hormones on the differentiation and function of cultured osteoblasts derived from 1-year-old Cohen diabetic rats. (The Cohen diabetic model consists of a diabetic-sensitive strain [CDs; diabetic] and a diabetic-resistant strain [CDr; normal]). The CDs and CDr male and female rats were fed on a regular diet (RD) or a high-sucrose low-copper diet (HSD; diabetogenic). On the HSD diet, only CD rats develop type 2 diabetes, while CDr do not. Bones were removed for primary osteoblast cultures, and osteoblastic responses to the bone-modulation hormones--estradiol, testosterone, and 1,25(OH)(2)D(3)--were studied. In male rats fed RD, primary cultures of osteoblasts without hormone addition to the culture medium showed that alkaline phosphatase (ALP) activity was similar in the Cohen diabetic rats (both CDr and CDs) to that of the original Sabra strain. However, collagen synthesis was reduced in the CDr and CDs compared to the Sabra strain. The addition of the hormones to the culture medium did not change ALP activity or collagen synthesis in the male-derived osteoblasts, but increased mineralization in all strains. In female rats (studied only in CDs and CDr animals) there were no differences between animals fed the RD. HSD increased the basal activity of ALP in the CDr but not in the CDs rats, and decreased the rate of collagen synthesis in both CDr and CDs (diabetic) animals. The addition of the bone-modulation hormones to the culture medium further increased ALP activity in the osteoblasts derived from the CDr animals, while decreasing ALP activity in the CDs. These hormones also decreased collagen synthesis in both strains and increased mineralization in all osteoblasts. In conclusion, the metabolic status (HSD and diabetes) in rats prior to culture affected the phenotype of cultured osteoblasts, decreasing their response to bone-modulation hormones. This decreased response, especially to estradiol, may be a major cause of the osteopenia observed in diabetes.
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PMID:Decreased response of osteoblasts obtained from aged Cohen diabetic sensitive rats to sex steroid hormones and 1,25OH2D3 in culture. 1699 16


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