Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

X-ray quality single crystals of an extracellular esterase from pathogenic Streptomyces scabies were obtained by the hanging drop method. The crystals are monoclinic (space group C2, a = 161.1 A, b = 51.2 A, c = 124.2 A, beta = 100.6 degrees) with two molecules related by a noncrystallographic dyad in the asymmetric unit, with a solvent content of approximately 64%. The diffraction pattern from fresh crystals extends beyond 2 A resolution using sealed tube CuK alpha radiation. The study has been initiated in order to elucidate the mechanism of this unusual non-serine-dependent esterase, and to gain better understanding of the molecular basis of the pathogenesis of the scab disease.
J Mol Biol 1992 Sep 20
PMID:Crystallization and preliminary crystallographic data of a Streptomyces scabies extracellular esterase. 140 70

A gene from Magnaporthe grisea was cloned using a cDNA clone of the Colletotrichum gloeosporioides cutinase gene as a heterologous probe; the nucleotide sequence of a 2 kb DNA segment containing the gene has been determined. DNA hybridization analysis shows that the M. grisea genome contains only one copy of this gene. The predicted polypeptide contains 228 amino acids and is homologous to the three previously characterized cutinases, showing 74% amino acid similarity to the cutinase of C. gloeosporioides. Comparison with previously determined cutinase sequences suggests that the gene contains two introns, 115 and 147 bp in length. The gene is expressed when cutin is the sole carbon source but not when the carbon source is cutin and glucose together or glucose alone. Levels of intracellular and extracellular cutinase activity increase in response to growth in the presence of cutin. The activity level is higher in a transformant containing multiple copies of the cloned gene than in the parent strain. Non-denaturing polyacrylamide gels stained for esterase activity show a single major band among intracellular and extracellular proteins from cutin-grown cultures that is not present among intracellular and extracellular proteins prepared from glucose-grown or carbon-starved cultures. This band stains more intensely in extracts from the multicopy transformant than in extracts from the parent strain. We conclude that the cloned DNA contains a M. grisea gene for cutinase, which we have named CUT1.
Mol Gen Genet 1992 Mar
PMID:Cloning and analysis of CUT1, a cutinase gene from Magnaporthe grisea. 155 23

Using a one-step strategy to disrupt CUT1, a gene for cutinase, cut1- mutants were generated in two strains of Magnaporthe grisea. One strain, pathogenic on weeping lovegrass and barley and containing the arg3-12 mutation, was transformed with a disruption vector in which the Aspergillus nidulans ArgB+ gene was inserted into CUT1. Prototrophic transformants were screened by Southern hybridization, and 3 of 53 tested contained a disrupted CUT1 gene (cut1::ArgB+). A second strain, pathogenic on rice, was transformed with a disruption vector in which a gene for hyg B resistance was inserted into CUT1. Two of the 57 transformants screened by Southern hybridization contained a disrupted CUT1 gene (cut1::Hyg). CUT1 mRNA was not detectable in transformants that contained a disrupted gene. Transformants with a disrupted CUT1 gene failed to produce a cutin-inducible esterase that is normally detected by activity staining on non-denaturing polyacrylamide gels. Enzyme activity, measured either with tritiated cutin or with p-nitrophenyl butyrate as a substrate, was reduced but not eliminated in strains with a disrupted CUT1 gene. The infection efficiency of the cut1- disruption transformants was equal to that of the parent strains on all three host plants. Lesions produced by these mutants had an appearance and a sporulation rate similar to those produced by the parent strains. We conclude that the M. grisea CUT1 gene is not required for pathogenicity.
Mol Gen Genet 1992 Mar
PMID:Disruption of a Magnaporthe grisea cutinase gene. 155 24

Sialic acid on human erythrocytes is involved in invasion by the human malaria parasite, Plasmodium falciparum. Mouse erythrocytes were used as a reagent to explore the question of whether erythrocyte sialic acid functions as a nonspecific negative charge or whether the sialic acid is a necessary structural part of the receptor for merozoites. Human erythrocytes contain N-acetylneuraminic acid (Neu5Ac), whereas mouse erythrocytes, which are also invaded by P. falciparum merozoites, contain 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac2) and N-glycoloylneuraminic acid (Neu5Gc), in addition to Neu5Ac. We compared the effects of sialidase and influenza C virus esterase treatments of mouse erythrocytes on invasion and the binding of a 175-kDa P. falciparum protein (EBA-175), a sialic acid-dependent malaria ligand implicated in the invasion process. Sialidase-treated mouse erythrocytes were refractory to invasion by P. falciparum merozoites and failed to bind EBA-175. Influenza C virus esterase, which converts Neu5,9Ac2 to Neu5Ac, increased both invasion efficiency and EBA-175 binding to mouse erythrocytes. Thus, the parasite and EBA-175 discriminate between Neu5Ac and Neu5,9Ac2, that is, the C-9 acetyl group interferes with EBA-175 binding and invasion by P. falciparum merozoites. This indicates that sialic acid is part of a receptor for invasion.
Mol Biochem Parasitol 1992 Mar
PMID:Binding of Plasmodium falciparum 175-kilodalton erythrocyte binding antigen and invasion of murine erythrocytes requires N-acetylneuraminic acid but not its O-acetylated form. 156 37

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

Estradiol-17 beta (E2) is converted exclusively to intracellular metabolites, termed lipoidal estrogens [long chain fatty acid 17 beta-esters (E2-L)], by human mammary cancer tissue and cell lines. In order to further evaluate the biological role of lipoidal estrogens, rates of saturation of the estrogen receptor (ER) along with formation of [3H]E2-L have been measured in human mammary cancer cells exposed to 5 nM [3H]E2. Extensive specific binding of E2 to ER in MCF-7 cells (approximately 37%) and ZR-75-1 cells (approximately 62%) occurred before appreciable synthesis of E2-L was evident and the maximum level of E2-L attained was only 3-9% of the E2 specifically bound to ER. In these ER positive cell lines, and in the ER negative cell line MDA-MB-231, an initial rise in the rate of E2-L formation was followed by a decrease at approximately 6 min and re-establishment of a new rate, indicating turnover of the E2-L fraction by esterification-de-esterification reactions. This data does not support the concept that E2-L acts in the transport of E2 to nuclear receptors, but rather than liberation of E2 from E2-L could serve to maintain occupancy of ER necessary for initiation of DNA synthesis. The esterase, as studied in pooled human mammary cancer tissue, was found to hydrolyse E2-17 beta-long chain fatty acid esters at different rates--the enzyme being less active towards E2-17 beta-stearate compared to E2-17 beta-oleate, -linoleate and -linolenate. Esterase activity was significantly higher in MDA-MB-231 cells compared to MCF-7 cells. Treatment of MCF-7 cells with E2 did not alter the specific activity of the esterase towards E2-17 beta-oleate as substrate. Similarly, addition of dibutyryl c-AMP to ZR-75-1 cell cultures was without effect on E2-L, both during the time when E2-L was accumulating, or during a subsequent phase when E2-L was decreasing following transfer to medium lacking E2. Calcitonin, which increases endogenous c-AMP in MCF-7 cells, had no effect on E2-L in this latter phase using this cell line. Thus, no evidence could be provided that the esterase was under E2 control, or control by polypeptide hormones which utilize c-AMP as a second messenger.
J Steroid Biochem Mol Biol 1991 Nov
PMID:Metabolism of lipoidal derivatives of estradiol-17-beta in human mammary cancer tissue and cell lines. 165 70

The success of axon regeneration after nerve injury should be judged by the extent to which the target organs regain their function. Recovery of muscle contraction involves axon regeneration, reestablishment of nerve-muscle connections, recovery of transmission, and muscle force. All these processes were investigated under the same experimental conditions and correlated in order to better understand their time-course and interdependence. The sciatic nerve of a rat was crushed in the thigh. The ingrowth of regenerating motor axons into the soleus (SOL) and extensor digitorum longus (EDL) muscles was monitored by measuring the activity of choline acetyltransferase (ChAT), a marker enzyme for cholinergic nerve terminals, in the muscles. The electron microscopic cytochemistry of acetylcholine esterase (AChE) was used to estimate the reestablishment of neuromuscular junctions in these two muscles. The recovery of muscle contraction was followed by measuring the force of isometric contraction in the triceps surae muscle in vivo. The pattern of ChAT recovery during reinnervation was similar in the EDL and SOL. The statistically significant increase of ChAT activity in these muscles, 14 d after the nerve crush, signified the entry of regenerating axons into the calf muscles. Electron microscopic cytochemistry revealed the first small nerve endings in contact with the denervated end plates 12 d after denervation. Subsequently, the number of reinnervated motor end plates and the surface area of the neuromusclar junctions steadily increased. The recovery of muscle force started between d 14 and 21 after the nerve crush. Thirty-five days after denervation, the difference between the muscle force of the reinnervated muscle and the control became statistically insignificant. Morphological normalization of the motor end plates was practically complete 33 d after denervation, concomitant with the normalization of the muscle force. At that time, however, ChAT activity in both muscles was still clearly subnormal (33.5% in EDL and 45% of the control in SOL) and therefore does not reflect the true extent of muscle force recovery. Yet, it seems that in spite of this, the regenerated nerve terminals contained sufficient amounts of acetylcholine (ACh) to trigger normal muscle contractions.
Mol Chem Neuropathol 1991 Oct
PMID:Biochemical, morphological, and functional changes during peripheral nerve regeneration. 177 90

The constitutive expression of 25-hydroxyvitamin D3-24-hydroxylase (25-(OH)D3-24-hydroxylase) activity has been studied in an adherent variant (Ad-HL60) of the human promyelomonocytic leukaemia cell line HL60. The Ad-HL60 cells have a more differentiated phenotype than the non-adherent cells from which they were derived, and synthesized 1.88 +/- 0.07 (+/- S.E.M.) pmol 24,25-(OH)2D3/h per 10(6) cells following culture in RPMI-1640 medium containing less than 0.02 nM 1 alpha,25-(OH)2D3. They also synthesized 1.66 +/- 0.05 pmol 24,25-(OH)2D3/h per 10(6) cells following culture in 1 alpha,25(OH)2D3-free medium supplemented with 1 g bovine serum albumin/l instead of 10% serum. In contrast, non-adherent HL60 cells required exposure to 10-100 nM 1 alpha,25-(OH)2D3 to induce equivalent 24,25-(OH)2D3 synthesis. The 25-(OH)D3-24-hydroxylase expressed by Ad-HL60 cells had an apparent Michaelis constant of 1 microM and maximal rate of 20 pmol/h per 10(6) cells with substrate concentrations from 0.012 to 1.2 microM/incubation (5-500 ng/ml). Furthermore, 24,25-(OH)2D3 synthesis was inhibited in a dose-dependent manner by ketoconazole (0.01-10 microM), suggesting that the enzyme is cytochrome P-450 dependent. Ad-HL60 cells expressed approximately 3500 specific receptors for 1 alpha,25-(OH)2D3/cell with a dissociation constant of 40 pM. Following exposure to 0.1-100 nM 1 alpha,25-(OH)2D3, Ad-HL60 cell proliferation was significantly inhibited compared with controls grown in medium containing less than 0.02 nM 1 alpha,25-(OH)2D3 for 96 h. Expression of 25-(OH)D3-24-hydroxylase was also inhibited in a dose- and time-dependent manner; however, expression of nonspecific esterase was not induced. Both of these findings are contrary to those previously demonstrated for non-adherent HL60 cells, whereas the dose-dependent inhibition of cell proliferation by 1 alpha,25-(OH)2D3 occurs in both adherent and non-adherent phenotypes. These observations on Ad-HL60 cells represent the first description of a cell type in which 1 alpha,25-(OH)2D3 appears to inhibit 25-(OH)D3-24-hydroxylase activity. The Ad-HL60 cells also constitutively metabolized 1 alpha,25-(OH)2D3 in a manner consistent with formation of 1 alpha,25-(OH)2D3 without previous exposure to 1 alpha,25-(OH)2D3. In contrast, many other cell types, including non-adherent HL60 cells, require exposure to 1 alpha,25-(OH)2D3 to induce metabolism of 1 alpha,25-(OH)2D3 to 1 alpha,24,25-(OH)3D3, a reaction that represents the initial step for catabolism of 1 alpha,25-(OH)2D3 to calcitroic acid.
J Mol Endocrinol 1991 Dec
PMID:Studies on an adherent variant of the human promyelomonocytic HL60 leukaemia cell line that constitutively expresses 25-hydroxyvitamin D3-24-hydroxylase activity which is inhibited by 1 alpha,25-dihydroxyvitamin D3. 177 40

Several years ago we discovered an unexpected family of steroidal metabolites, steroidal fatty acid esters. We found that fatty acid esters of 5-ene-3 beta-hydroxysteroids, pregnenolone and dehydroisoandrosterone are present in the adrenal. Subsequently, others have shown the existence of these non-polar 5-ene-3 beta-hydroxysteroidal esters in blood, brain and ovaries. Currently, almost every family of steroid hormone is known to occur in esterified form. We have studied the esters of the estrogens and glucocorticoids in some detail, and have found that these two steroidal families are esterified by separate enzymes. In a biosynthetic experiment performed simultaneously with estradiol and corticosterone, we established that the fatty acid composition of the steroidal esters is quite different. The corticoid is composed predominantly of one fatty acid, oleate, while the estradiol esters are extremely heterogeneous. Our studies have demonstrated that the estrogens are extremely long-lived hormones, that they are protected by the fatty acid from metabolism. They are extremely potent estrogens, with prolonged activity. Esterification appears to be the only form of metabolism that does not deactivate the biological effects of estradiol. We have demonstrated the biosynthesis of fatty acid esters of estriol, monoesters at both C-16 alpha and C-17 beta. They too are very potent estrogens. These fatty acid esters of the estrogens are the endogenous analogs of estrogen esters, like benzoate, cypionate, etc., which have been used for decades, pharmacologically because of their prolonged therapeutic potency. We have found that the estradiol esters are located predominantly in hydrophobic tissues, such as fat. Sequestered in these tissues, they are an obvious reservoir of estrogenic reserve, requiring only an esterase for activation. To the contrary the biological activity of the fatty acid esters of the glucocorticoid, corticosterone, is not different from that of its free parent steroid. We have shown that the rapid kinetics of its induction of gluconeogenic responses is caused by its labile C-21 ester which is rapidly hydrolyzed by esterase enzymes. While it appears that the physiological role of the estrogen esters may be related to their long-lived hormonal activity, the role of the other families of steroidal esters is not yet apparent. They, and perhaps the estrogen esters as well, must serve other purposes. Indeed they may serve important biological functions beyond those which we ordinarily associate with steroid hormones.
J Steroid Biochem Mol Biol 1991
PMID:Steroidal fatty acid esters. 183 47

In earlier studies, we had determined that class II (Ia) major histocompatibility complex (MHC) antigen expression in the normal rat lung was limited to dendritic cells and type II alveolar cells. In order to characterize the Ia+ pulmonary dendritic cells of the lung parenchyma, Lewis rat lungs were dissected free of their major airways, enzymatically digested, and serially subjected to density centrifugation on bovine serum albumin, overnight adherence, and immunopanning with a murine anti-rat monoclonal antibody (anti-OX-6) that reacts specifically with class II (Ia) MHC antigens. The purified Ia+ pulmonary cells displayed the morphologic and functional features of dendritic accessory cells, including extended cell processes, absence of nonspecific esterase staining, minimal phagocytosis of latex beads, rapid clustering with T lymphocytes, and co-stimulation of T-cell mitogen responses. Detailed immunophenotyping by cytofluorimetry and immunohistology showed that the purified dendritic cells were Ia (OX-6)+, CD45R (OX-1)+, CD45Rb (OX-22)-, ICAM-1+, and OX-43-. As many as 50% of the cells bound heat-aggregated IgG, while a smaller percentage expressed the CD43 sialophorin antigens (W3/13) expressed by a variety of blood-derived cells, and/or the OX-41 and RMA macrophage antigens. We conclude that Ia+ dendritic cells of lung are heterogeneous with respect to their expression of surface membrane differentiation antigens and may prove to be functionally distinct with respect to their accessory activities.
Am J Respir Cell Mol Biol 1991 Sep
PMID:Accessory cells of the lung. II. Ia+ pulmonary dendritic cells display cell surface antigen heterogeneity. 191 Aug 13


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