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

---

Query: EC:3.1.6.1 (sulfatase)
3,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

35S-labeled sulfate esters of dehydroepiandrosterone and 16 alpha-hydroxydehydroepiandrosterone were synthesized and used as substrates for the in vitro kinetic assay of human placental steroid-sulfatase. Both steroid sulfates were hydrolysed by placenta homogenates and microsomal fractions with V values comparable to each other. The Km value of the 16 alpha-hydroxy compound, however, was found to be about tenfold higher than that of dehydroepiandrosterone sulfate. Both sulfate esters competitively inhibited each other's hydrolysis. The results suggest that dehydroepiandrosterone sulfate, as compared to its 16 alpha-hydroxy derivative, is the preferred substrate of the sulfatase. As far as conclusions can be drawn from experiments in vitro, this finding excludes the possibility that the preponderance of placental estriol production over that of estradiol and estrone in human late pregnancy is due to a preferential binding and cleavage of the estriol precursor 16 alpha-hydroxydehydroepiandrosterone sulfate by the placental steroid-sulfatase.
...
PMID:Human placental steroid-sulfatase. Kinetics of the in-vitro hydrolysis of dehydroepiandrosterone 3-sulfate and of 16 alpha-hydroxydehydroepiandrosterone 3-sulfate. 622 Sep 52

The conversion of tritium-labeled estrone sulfate to [3H]estrone was evaluated in human lung tissue in vitro. Under standardized conditions, the rate of hydrolysis of [3H] estrone sulfate to [3H]estrone was linear with time of incubation up to 4 h and with wet tissue weight up to 400 mg/ml. The apparent Km of sulfatase for estrone sulfate was 9 microM, and the maximum velocity was 1.4 nmol substrate hydrolyzed/100 mg lung . h. The lung tissue also metabolized the primary metabolite of [3H]estrone sulfate, [3H]estrone, to 17 beta-[3H]estradiol. The hydrolysis of [3H]dehydroisoandrosterone sulfate to [3H]dehydroisoandrosterone by human lung tissue was also measured. Sulfatase activity with this substrate was linear as a function of wet tissue weight up to 800 mg/ml. The apparent Km of sulfatase for dehydroisoandrosterone sulfate was 7 microM, and the maximum velocity was 1.0 nmol substrate hydrolyzed/100 mg lung . h. The highest specific activity of lung sulfatase for [3H]dehydroisoandrosterone sulfate was found in a microsomal fraction of lung homogenate. The primary metabolite, [3H]dehydroisoandrosterone, was metabolized further by lung tissue to [3H]androstenedione and [3H]5-androstene-3 beta, 17 beta-diol. Although isolated segments of human pulmonary arteries also metabolized both [3H] estrone sulfate and [3H]dehydroisoandrosterone sulfate, cultures of pulmonary arterial endothelial cells lacked sulfatase activity. The cell(s) source of sulfatase activity in human lung tissue and isolated arteries has not yet been identified. Our findings suggest that the metabolism of sulfated steroids by the lung should be considered in evaluating homeostasis.
...
PMID:Steroid sulfatase activity in human lung tissue and in endothelial pulmonary cells in culture. 622 60

SWR/J mice possess two- to threefold higher 4-methylumbelliferyl sulfate (4MUS), dehydroepiandrosterone sulfate (DHEAS) and estrone sulfate (E1S) sulfatase activities in liver and kidney extracts than do A/J mice. These interstrain activity differences are maintained throughout the 6- to 45-day postnatal period. Characteristics of the hepatic activities of SWR/J mice suggest that all three activities reside in the same enzyme. Biochemical properties of the SWR/J and A/J enzyme were not significantly different. Expression of hepatic enzyme activity is subject to regulation by an autosomal locus possessing two alleles with additive effects. Postnuclear E1S- and DHEAS-sulfatase activities are primarily microsomal. Although postnuclear hepatic 4MUS-sulfatase activity is predominantly microsomal, renal activity is primarily nonmicrosomal. Only that portion of 4MUS-sulfatase occurring in cell membranes appears capable of hydrolyzing E1S and DHEAS. The hepatic- and renal-specific subcellular distributions of 4MUS-sulfatase activity may reflect tissue differences in enzyme processing. Renal 4MUS-sulfatase activity is also controlled by an autosomal gene with two alleles having additive effects. Positive correlation between hepatic and renal 4MUS-sulfatase activities indicates that both activities are most likely influenced by the same gene.
...
PMID:Genetic analysis of murine arylsulfatase C and steroid sulfatase. 622 98

A new, simple, fast and highly practicable sulfatase assay and its application is described. Sterol sulfatase sulfohydrolase (EC 3.1.6.2) activity is determined by a two-phase scintillation technique separating the unreacted [4-14C]dehydroepiandrosterone sulfate from carbon-14-labeled products. The principle of the separation relies on the limited emulsifying capacity of the dioxane-based scintillation solution for water and the different partition of dehydroepiandrosterone sulfate and sulfate-free steroid products between the scintillation fluid and the aqueous phase as recently applied for determination of aromatase activity [1]. [7-3H]Dehydroepiandrosterone sulfate can also be used as a substrate for this assay. This test was applied to studies of microsomal sulfatase prepared from human term placenta and to the detection of sulfatase activity in human skin biopsies. Using placental microsomes, the Km of dehydroepiandrosterone sulfate was determined to be 5.0 X 10(7)M. Sulfatase activity in frozen scrotal skin was found to be 2-3 fold than with vaginal skin. Using an incubation time of 24h/skin sulfatase can be detected in biopsies as small as 2.5 mm2. The sulfatase assay can be applied for routine detection of human placental sulfatase deficiency and, furthermore, the application of this assay has to be demonstrated for the analysis of sulfatase activity in patients with congenital ichthyosis (X-chromosomal, recessive type).
...
PMID:New assay for steroid sulfatase (EC 3.1.6.2) and its application for studies of human placental and skin sulfatase. 636 91

The metabolism of endogenous estrogens, estradiol and estrone, and the irreversible binding of estrogens to cellular macromolecules have been examined and compared in subcellular microsomal and in intact hepatocyte preparations. In studies with rat liver microsomal preparations containing estradiol, an NADPH-generating system, and denatured DNA, the irreversible binding of radiolabeled steroid metabolite(s) to the microsomal proteins was 3.26 nmoles/mg protein in 1 hr (S.D. 0.39; 7.9% of total steroid) while binding to DNA was found to be 0.288 nmole/mg DNA/mg protein (S.D. 0.025; 0.39% of total steroid). No significant difference was observed between microsomal preparations from untreated, phenobarbital-treated or 3-methylcholanthrene-treated rats. Irreversible binding to proteins was also demonstrated in the intact hepatocyte cell incubations. After 2-hr incubations of estradiol with hepatocytes, 5.9% (S.D. 1.4%) of the steroid(s) was irreversibly associated with cellular proteins (approximately 1.43 pmoles/mg/min). Analysis of the organic-soluble metabolites demonstrated the presence of the catechol estrogens and their metabolites, 2-hydroxyestradiol, 2-hydroxyestrone, 2-methoxyestradiol, and 2-methoxyestrone. Estrone and estriol were also identified. The aqueous-soluble materials isolated from hepatocyte incubations contained glucuronide, sulfate, and apparent thioether conjugates, as determined by liberation from estrogen metabolites by treatment with beta-glucuronidase, sulfatase, and Raney nickel. Thus, extensive primary and secondary metabolism of estrogens occurs in intact hepatocyte incubations. Furthermore, irreversible binding of estrogens to cellular proteins occurs in these intact cells having demonstrated conjugative pathways of metabolism.
...
PMID:Estrogen metabolism in rat liver microsomal and isolated hepatocyte preparations--I. Metabolite formation and irreversible binding to cellular macromolecules. 650 37

Dependence on the salt concentration of the activity of microsome-bound arylsulfatase C [EC 3.1.6.1] from rat liver was examined. The activity increased with increasing salt concentration in the reaction medium in the whole pH range tested. This effect can be explained by the dependence of the reaction rate on the surface pH and the surface concentration of the ionic substrate. The dependence on salt concentration of the activity of the microsome-bound arylsulfatase C and the pH-dependences of Vmax and Km of the enzyme were used for the estimation of pH at the microsomal surface. The two values of the surface pH (surface potential) and the salt concentration were applied to the Gouy-Chapman equation. The value of -0.39 +/- 0.08 X 10(-3) elementary charge/A2 was obtained as the surface charge density in the vicinity of the microsome-bound arylsulfatase C. This was smaller than the over-all value for microsomes (-1.08 +/- 0.04 X 10(-3) elementary charge/A2; Masamoto, K. (1982) J. Biochem. 92, 365-371). This suggests that the anion concentration in the vicinity of the enzyme on microsomes is lower than that in the bulk aqueous phase and is higher than the average value at the microsomal surface when the salt concentration is low.
...
PMID:Dependence on surface pH and surface substrate concentration of activity of microsome-bound arylsulfatase C and the surface charge density in the vicinity of the enzyme. 658 19

Magnum from quail oviduct was subfractionated to yield epithelium and tubular glands. The in vitro enzymatic activities involved in sulfated sugar nucleotide biosynthesis were assayed in these isolated tissues. The results demonstrated that the activities necessary for a series of reactions, UDP-N-acetylgalactosamine----UDP-N-acetylgalactosamine 4-sulfate----UDP-N-acetylgalactosamine 4,6- bisulfate ----UDP-N-acetylgalactosamine 6-sulfate, are located predominantly in the tubular gland. Both time course and pulse-chase studies with [35S]sulfate gave results that were consistent with this reaction scheme. A microsomal preparation from the magnum was shown to be capable of labeling all three sulfate sugar nucleotides with [35S]sulfate upon incubation with UDP-N-acetylgalactosamine and 3'- phosphoadenylyl [35S]sulfate. Again, their relative labeling rates were in the order necessary to allow for a synthesis of sulfated sugar nucleotides in the sequence described above. Furthermore, incubation of the microsomal preparation with UDP-N-[14C]acetylgalactosamine 4-sulfate and 3'- phosphoadenylyl sulfate resulted in the formation of UDP-N-[14C]acetylgalactosamine 6-sulfate. Also shown was the existence in the microsomal preparation of a sulfatase specific for the sulfate at position 4 of UDP-N-acetylgalactosamine 4,6- bisulfate . The results, together with those obtained in previous investigations, suggest that the tubular gland of quail oviduct contains a microsomal multienzyme system which catalyzes a series of sulfation and desulfation of N-acetylgalactosamine residues at the nonreducing terminal position of either sugar nucleotides or polysaccharide chains.
...
PMID:A sulfotransferase-sulfatase system in avian oviduct which catalyzes a conversion of UDP-N-acetylgalactosamine 4-sulfate to the 6-sulfate isomer. 658 20

Estrone and dehydroepiandrosterone (DHA) sulfatase activities were studied in the uterus and liver of female guinea-pigs (albino variety). The two activities were found in particulates, with the highest specific activity in microsomes. The effects of pH, buffers, temperature and the non-competitive inhibition of DHA sulfate on estrone sulfatase provided arguments for the existence of two distinct sulfatases. However, acrylamide gel electrophoresis of the solubilized microsome sulfatases gave a single peak for the two activities. In the uterus, the apparent Km of estrone and DHA sulfatases were 26.4 and 15.6 microM. Solubilized microsomal estrone sulfatase was inhibited by unconjugated steroids. The apparent Km of estrone sulfatase in liver was 10.7 microM. Estrone and DHA sulfatase activities were consistently lower in liver than in uterus and no DHA sulfatase activity was detected in fetal liver. In the uterus, the same sulfatase activities were found in female fetuses, castrated or mature females. Estrone sulfatase was significantly increased in the uterus of pregnant females (60-65 days gestation). Estrone sulfate was injected in vivo into mature castrated females. A significant increase in uterine weight and in uterine progesterone receptors was observed. The cytosol progesterone receptors were characterized by their Kd (1.40 nM) and by sucrose density gradient. It is concluded that the variations of estrone sulfatase activity in target tissues like the uterus may control the intracellular levels of biologically active estrogens.
...
PMID:Estrone and dehydroepiandrosterone sulfatase activities in guinea-pig uterus and liver: estrogenic effect of estrone sulfate. 659 7

Although the deficiency of steroid sulfatase (STS) as well as aryl sulfatase C (ASC) activities in patients with X-linked recessive ichthyosis has been confirmed by several groups all over the world, the question whether STS = ASC is not yet completely answered. To obtain more information, Miranol H2M extracts from placental microsomes and cultured skin fibroblasts were subjected to gel permeation chromatography and polyacrylamide gel electrophoresis. STS (3H-dehydroepiandrosterone sulfate) and ASC (4-methylumbelliferone sulfate) activities were estimated in the eluted gel permeation chromatography fractions and within the same gel cylinders in half gel slices. None of these two methods allowed a separation of the two microsomal sulfatase activities. From these results and from different behavior of STS and ASC (not deficient in uncultured skin preparations of X-linked recessive ichthyosis, different kinetic properties between STS and ASC, etc.) we propose microsomal sulfatase activities to be assembled in an enzyme aggregate.
...
PMID:Steroid sulfatase = aryl sulfatase C? Chromatographic and electrophoretic properties in extracts from placental microsomes and skin fibroblasts. 659 86

The combined occurrence of X-linked steroid sulfatase deficiency of the placenta and X-linked ichthyosis is reported in 6 unrelated boys. Placental steroid sulfatase deficiency was diagnosed on the basis of a very low total estrogen excretion (6 cases), verified prenatally by the dehydroepiandrosterone sulfate (DHEAS) loading test in 4 cases and postnatally by clinical investigations (6 cases) and by biochemical investigations (5 cases). In addition, microsomal arylsulfatase C (MAS) could not be detected in the placental homogenate of the five cases investigated. Lysosomal arylsulfatases were within the normal range. All boys developed well except for X-linked ichthyosis. In the 5 cases investigated the skin biopsy showed the same MAS deficiency histochemically in the granular layer of the epidermis as in the trophoblast cells. The same holds true for the skin of carriers. Steroid sulfatase activity of cultured skin fibroblasts from the boys was almost nil (3 cases). The histochemical technique offers a practical approach in the scientific investigation of keratotic conditions.
...
PMID:X-linked ichthyosis and X-linked placental sulfatase deficiency: a disease entity. Histochemical observations. 692 54


<< Previous 1 2 3 4 5 6 7 8 9 Next >>

---