Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Mammalian estrogen sulfotransferase (EST; EC 2.8.2.4) sulfurylates the hydroxyl group of estrogenic steroids by transferring the sulfate from a cosubstrate adenosine 3'-phosphate-5'-phosphosulfate. Sulfurylated steroids do not bind to the estrogen receptor with high affinity and, therefore, are hormonally inactive. We have purified rat liver EST and developed monoclonal antibody to this enzyme. By immunoscreening a lambda gt-11 expression library constructed from male rat liver cDNAs, the cDNA clone corresponding to EST was identified and isolated. A recombinant expression plasmid (pCMV5) containing this cDNA insert when transfected into COS-7 cells generated both immunologically and enzymatically active EST. With the help of this cDNA probe, we have explored the regulation of the EST mRNA in the liver and the possible role of this enzyme in sex hormone action. During the lifespan of male rats, only the young adult animals show hepatic androgen responsiveness. Also, estrogenic hormones strongly antagonize androgen action in the rat liver. Northern blot analysis of liver RNA derived from male rats of different ages shows that the androgen sensitivity of young adult animals is associated with a high expression of EST mRNA. During the same period, mRNA corresponding to dehydroepiandrosterone sulfotransferase is markedly (approximately 10-fold) down-regulated. Such a correlation is in concordance with the role of these enzymes in the maintenance of hepatic androgen sensitivity during young adult life by inactivating the estrogenic and sparing the androgenic steroids. Furthermore, the increase in the hepatic androgen sensitivity of androgen-treated female rats is also associated with the induction of EST.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Endocrinol 1992 Apr
PMID:Estrogen sulfotransferase of the rat liver: complementary DNA cloning and age- and sex-specific regulation of messenger RNA. 137 39

The esterase 5 (Est-5 = gene, EST 5 = protein) enzyme in Drosophila pseudoobscura is encoded by one of three paralogous genes, Est-5A, Est-5B, and Est-5C, that are tightly clustered on the right arm of the X chromosome. The homologous Est-6 locus in Drosophila melanogaster has only one paralogous neighbor, Est-P. Comparisons of coding and flanking DNA sequences among the three D. pseudoobscura and two D. melanogaster genes suggest that two paralogous genes were present before the divergence of D. pseudoobscura from D. melanogaster and that, later, a second duplication occurred in D. pseudoobscura. Nucleotide sequences of the coding regions of the three D. pseudoobscura genes showed 78-85% similarity in pairwise comparisons, whereas the relatedness between Est-6 and Est-P was only 67%. The higher degree of conservation in D. pseudoobscura likely results from the comparatively recent divergence of Est-5B and Est-5C and from possible gene conversion events between Est-5A and Est-5B. Analyses of silent and replacement site differences in the two exons of the paralogous and orthologous genes in each species indicate that common selective forces are acting on all five loci. Further evidence for common purifying selective constraints comes from the conservation of hydropathy profiles and proposed catalytic residues. However, different levels of amino acid substitution between the paralogous genes in D. melanogaster relative to those in D. pseudoobscura suggest that interspecific differences in selection also exist.
J Mol Evol 1992 Jun
PMID:An evolutionary model for the duplication and divergence of esterase genes in Drosophila. 159 43

A clone of the esterase-5 (Est-5) gene from Drosophila pseudoobscura has been isolated by hybridization to the cloned Est-6 gene of D. melanogaster. Southern analysis and sequencing of the cloned DNA revealed three regions of similarity to Est-6 that have been tentatively identified as genes, Est-5A, Est-5B, and Est-5C. Introduction of each of the three genes separately into D. melanogaster by P-element transformation has demonstrated that Est-5B encodes an enzyme with the same physical properties as EST 5 in D. pseudoobscura. Sequence analysis indicates that Est-5B encodes a 545-amino-acid protein and is composed of two exons separated by a 55-bp intron in the same position as the 51-bp intron in Est-6. Comparison of the Est-5B coding region with that of Est-6 reveals an overall similarity (73% at both the nucleotide and amino acid levels) that is substantially lower than that for other genes sequenced in both of these species. Total nucleotide and nonsynonymous site differences between Est-6 and Est-5B are more abundant in the second exon than in the first, suggesting differential effects of selection or mutation on these two exons. Comparisons of the 5'-flanking DNA of Est-5B and Est-6 reveal four short conserved sequence elements, but the remaining upstream sequences show no significant similarity. Conservation in the 3'-flanking DNA is limited to the presence of two polyadenylation sites that may correlate with the existence of two transcripts from both Est-5B and Est-6. The patterns of nucleotide substitutions and amino acid replacements between Est-5B and Est-6 are consistent with the hypothesis that mutation and genetic drift are responsible for the differences between these two genes.
Mol Biol Evol 1990 Nov
PMID:Cloning of the esterase-5 locus from Drosophila pseudoobscura and comparison with its homologue in D. melanogaster. 217 9

Most natural populations of Drosophila melanogaster are polymorphic for two major electrophoretic variants at the esterase-6 locus. The frequency of the EST 6F allozyme is greatest in populations in warmer latitudes, whereas the EST 6S allozyme is predominant in colder latitudes. Latitudinal clines in electromorph frequencies are found on three continents. Purified preparations of the allozymes have been characterized for their pH optimum, substrate specificity, organophosphate inhibition, alcohol activation, thermal stability, and kinetic parameters. These and previous analyses of the EST 6 allozymes reveal that the two variants have differences in their physical and kinetic properties that may provide a basis for the selective maintenance of the polymorphisms and an explanation of the clinal variation observed in natural populations.
Mol Biol Evol 1988 Jan
PMID:Studies of esterase 6 in Drosophila melanogaster. XVIII. Biochemical differences between the slow and fast allozymes. 312 16

ESR-spectrometry without modulation of the magnetic field was used for registering the EST spectral line shape (with shape distortion about 0.1 percent) of spin-labeled Escherichia coli tRNAPhe. The analysis of line shape of two different spin-labels in position 8 (S4U) revealed that tRNAPhe in solution always exists as a mixture of at least two conformers, the equilibria between conformers being dependent on pH, concentration of magnesium and the biological state of tRNA (deacylated, aminoacyl- or peptidyl-tRNA). There are no large structural rearrangements upon aminoacylation or peptidylation of tRNA, the observed small changes of spectral line shape are due to the changes in conformational equilibria.
Mol Biol (Mosk)
PMID:[Study on the conformational state of Escherichia coli tRNA-Phe in solution by ESR-spectometry without modulation]. 617 94

We have used a combination of chromosome-mediated gene transfer and microcell fusion techniques to transfer Chinese hamster chromosome 1 to mouse cells. Microcell hybrids containing a single hamster chromosome were analyzed to map genes on this chromosome. We have confirmed the assignment of seven markers (GSR, NP, EST-D, ADK, PEP-S, PGM2, and PEP-B) to hamster chromosome 1. Segregation among the linked markers was induced by X irradiation followed by selection for the retention or loss of human hprt. Cosegregation of markers in independent subclones made it possible to determine the gene order for the seven loci. The gene order proposed for these loci is as follows: pter-GSR-NP-EST-D-ADK-(PEP-S, PGM2)-PEP-B-qter. In addition GSR, NP, EST-D, and ADK have been assigned to pter-1q12; PEP-S and PGM2 to 1q12-1q21, and PEP-B to 1q32-1qter. These regional assignments and gene order on chromosome 1 have provided the information relevant to the linkages conserved between Chinese hamster, mouse, and man.
Somat Cell Mol Genet 1984 Nov
PMID:Transfer of Chinese hamster chromosome 1 to mouse cells and regional assignment of 7 genes: a combination of gene transfer and microcell fusion. 623 97

We have examined the effects of hypophysectomy and treatment with thyroxine (T4) on enzyme activity and expression (as determined by immunoblot analysis) of members of the three principal sulfotransferase (ST) sub-families (phenol STs, PST; estrogen STs, EST; hydroxysteroid STs, HST) in cytosols prepared from female Wistar rat livers. The results demonstrate that in female rat liver cytosol, EST activity was decreased by treatment with T4, increased following hypophysectomy and that treatment of hypophysectomized animals with T4 also greatly reduced EST activity. T4 had no significant effect on PST or HST activity in normal animals, but it decreased HST activity in hypophysectomized rat liver cytosol. Immunoblot analysis of these cytosols with antibodies recognising HST and PST indicated that where changes in enzyme activity occurred they mirrored changes in enzyme protein expression. In normal adult female rat livers, EST protein is not expressed, and the small residual activity results predominantly from the action of HST. Hypophysectomy induced EST activity and the expression of EST enzyme protein in female rat liver cytosol, and T4 treatment of hypophysectomized animals reduced the activity to below normal levels without reducing the corresponding enzyme protein levels, indicating that T4 regulation of EST in females is via a post-translational mechanism.
J Steroid Biochem Mol Biol 1995 Nov
PMID:Induction of hepatic estrogen sulfotransferase expression by hypophysectomy in female rats. 749 6

To understand the subcellular roles and the regulation of vacuolar H(+)-ATPases, we have begun to identify the genes encoding the major subunits and to determine their patterns of expression in Arabidopsis thaliana. Two distinct cDNAs (AVA-P1 and AVA-P2) and one genomic sequence (AVA-P3) encoding the 16 kDa subunit have been isolated. The 16 kDa proteolipid is a major component of the membrane integral sector that forms the proton conductance pathway and is required for assembly of the V-ATPase complex. Interestingly, the open reading frame of one full-length cDNA (AVA-P1) and a genomic sequence (AVA-P3) encoded an identical polypeptide of 164 amino acids with a molecular mass of 16,570. The deduced amino acid sequences of the two cDNAs were nearly identical (99%) and hydropathy plots suggested a molecule with four membrane-spanning domains characteristic of V-ATPase proteolipids. The three genes differed mainly in their codon usage and in their 3'-untranslated regions. The coding region of the genomic sequence, AVA-P3, was interrupted by two introns located at the codons for Cys-26 and Arg-121. The presence of additional 16 kDa proteolipid genes was suggested from several polymerase chain reaction (PCR)-amplified fragments that differed from one another in the size of the second intron. PCR 1 had an intron of ca. 800 bp and its identity as AVA-P4, a fourth member of the gene family, was confirmed from sequence analyses of an EST cDNA. The mRNAs of three genes (AVA-P1, AVA-P2 and AVA-P3) were detected in Arabidopsis leaf, root, flower and silique; yet expression of AVA-P1 and AVA-P2 was lower in roots. All three genes were expressed in light- or dark-grown seedlings; however mRNA levels of AVA-P2 were enhanced in etiolated plants. Arabidopsis thaliana, therefore, has at least four distinct genes encoding nearly identical 16 kDa proteolipids, and the enhanced expression of AVA-P2 transcript in etiolated seedlings suggests that an increase in V-ATPase could accompany cell expansion.
Plant Mol Biol 1995 Oct
PMID:Several distinct genes encode nearly identical to 16 kDa proteolipids of the vacuolar H(+)-ATPase from Arabidopsis thaliana. 757 75

A distinct human estrogen sulfotransferase (hEST-1) cDNA has been isolated from a human liver lambda Zap cDNA library using a PCR procedure. The enzymatically active protein has been expressed in two bacterial expression systems and the kinetic and immunologic properties of the enzyme have been characterized. The full-length cDNA for hEST-1 is 994 base pairs in length and encodes a 294 amino acid protein with a calculated molecular mass of 35,123 Da. Purified hEST-1 migrated with an apparent molecular mass of 35,000 Da during SDS-polyacrylamide gel electrophoresis. Immunoblot analysis of hEST-1 expressed in E. coli with a rabbit anti-hEST-1 antibody yields a band of approximately 35,000 Da. The anti-hEST-1 antibody also detects a single band in human liver and jejunum cytosol which migrates with the same molecular mass as expressed hEST-1. There was also no cross-reactivity of hEST-1 with rabbit anti-hP-PST or rabbit anti-hDHEA-ST antibodies upon immunoblot analysis. hEST-1 was expressed in bacteria and purified to homogeneity. Expressed hEST-1 activity has a significantly greater affinity for estrogen sulfation than that found for the other human STs which conjugate estrogens. hEST-1 maximally sulfates beta-estradiol and estrone at concentrations of 20 nM. hEST-1 also sulfates dehydroepiandrosterone, pregnenolone, ethinylestradiol, and 1-naphthol, at significantly higher concentrations; however, cortisol, testosterone and dopamine are not sulfated. The results presented in this paper describe the expression and characterization of a human EST distinct from other human STs which sulfate estrogens. The high affinity of hEST-1 for estrogens indicates that this ST may be important in both the metabolism of estrogens and in the regulation of their activities.
J Steroid Biochem Mol Biol 1995 Jun
PMID:Bacterial expression and characterization of a cDNA for human liver estrogen sulfotransferase. 777 57

Esterase enzymatic activity was investigated in salivary gland lysates of adult Aedes aegypti. Esterases in lysates made from female glands had higher specific activity than those in lysates from male glands towards beta-naphthyl acetate but showed no difference with alpha-naphthyl butyrate as a substrate. Female salivary gland lysates showed no difference in activity to alpha- and beta-forms of naphthyl acetate and no discernable activity towards alpha-naphthyl caprate. Both female and male salivary gland lysates exhibited phosphatase enzymatic activity but the specific activities were lower than those seen for the esterase enzymatic activity. Salivary gland esterase activity was inhibited completely by paraoxon, para-hydroxymercurobenzoate, tetraethylammonium iodide and moderately by diisopropylfluorophosphate. Eserine and phenylmethylsulfonylfluoride had no effect on enzyme activity. In a probing assay, adults of both sexes were shown to secrete esterase in saliva. Esterase activity was present in the saliva of females probing for either a sugar meal or a blood meal. Furthermore, esterase was secreted from female salivary glands in culture. Histochemical analysis of dissected salivary glands showed that the majority of the esterase enzymatic activity was in the distal-lateral lobes of the female tissues, although the proximal-lateral and medial lobes also had activity. Male salivary glands stained uniformly over all of the lobes. A salivary gland-specific esterase, designated SG-EST, appears to account for the majority of enzyme activity in the glands. SG-EST was partially purified by electroelution of an active protein from native polyacrylamide gels, and has an approximate molecular weight of 65,000 Da. In separate experiments, affinity chromatography independently identified a single 65,000 Da protein likely to be SG-EST. Native electrophoretic analysis of salivary glands revealed that, while most enzyme activity is due to SG-EST, there are two other esterases present. One of these minor moieties is present in adult tissues in addition to the salivary gland, and the other is present throughout development. Possible functions of the salivary gland esterase are discussed.
Insect Biochem Mol Biol 1995 May
PMID:Characterization of a salivary gland-specific esterase in the vector mosquito, Aedes aegypti. 778 44


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