Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hybridoma cells used for the production of monoclonal antibodies are also known to form growth inhibitory substances. Growth inhibitors already described in the literature belong to the class of peptides and proteins likeTGF-ss (Transforming Growth Factor-ss). The endogenous retrovirus particles - a further potential substance producing this kind of effect - are described here. To examine whether the retrovirus particles participated in growth inhibitory effects hybridoma cells were cultivated in continuous perfusion mode by using a special reactor set-up. A rapid increase of the signal in the supernatant which coincided with a decrease of viability could be observed by monitoring the reverse transcriptase-activity during this type of fermentation process. The examination of concentrated and fractionated supernatant from this period showed growth inhibitory effects in the biological assay (MTT-assay). Investigations of respective fractions demonstrated retrovirus particles with reverse transcriptase-activity. Based on RT-PCR data it was shown that only inhibitory fractions contain retrovirus particles which were of E-MuLV and MCF origin.
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PMID:Endogenous retrovirus particles and their repercussion effects on the growth behaviour of continuous hybridoma cultivation processes. 1900 5

A protein exhibiting an N-terminal amino acid sequence with some similarity to imidazoleglycerol phosphate synthase was purified from fresh Capparis spinosa melon seeds. The purification protocol entailed anion exchange chromatography on DEAE-cellulose, cation exchange chromatography on SP-Sepharose, and finally gel filtration by fast protein liquid chromatography on Superdex 75. The protein was adsorbed using 20 mM Tris-HCl buffer (pH 7.4) and desorbed using 1 M NaCl in the starting buffer from the DEAE-cellulose column and SP-Sepharose column. The protein demonstrated a molecular mass of 38 kDa in gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that it was monomeric. The protein inhibited proliferation of hepatoma HepG2 cells, colon cancer HT29 cells and breast cancer MCF-7 cells with an IC(50) of about 1, 40 and 60 microM, respectively. It inhibited HIV-1 reverse transcriptase with IC(50) of 0.23 microM. It inhibited mycelial growth in the fungus, Valsa mali. It did not exhibit hemagglutinating, ribonuclease, mitogenic or protease inhibitory activities.
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PMID:A protein with antiproliferative, antifungal and HIV-1 reverse transcriptase inhibitory activities from caper (Capparis spinosa) seeds. 1901 43

A trypsin inhibitor with a molecular mass of about 19 kDa was isolated from seeds of Chinese black soybean Glycine max cv. "Small Glossy Black". It was isolated using a protocol that comprised ion exchange chromatography on Q-Sepharose, SP-Sepharose and DEAE-cellulose. It was adsorbed on all three ion exchangers. It inhibited trypsin with an IC(50) of 19 microM and chymotrypsin with an IC(50) of 14.3 microM. Its trypsin inhibitory activity was stable in the pH range pH 3-pH 13 and in the temperature range 0 degree C-60 degrees C. The trypsin inhibitor was inhibited by dithiothreitol (from 5 to 25 mM) in a dose-dependent manner. It exhibited an N-terminal sequence highly homologous to Kunitz-type trypsin inhibitors. It inhibited HIV-1 reverse transcriptase with an IC(50) of 0.16 microM, and suppressed proliferation of MCF-7 breast cancer cells with an IC(50) of 4.3 microM and HepG2 hepatoma cells with an IC(50) higher than 25 microM. The trypsin inhibitor lacked antifungal activity and mitogenic activity towards mouse splenocytes.
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PMID:A trypsin-chymotrypsin inhibitor with antiproliferative activity from small glossy black soybeans. 1923 24

Three trypsin-chymotrypsin inhibitors were isolated from seeds of the black gram (Vigna mungo) with a procedure that entailed cation exchange chromatography on SP-Sepharose, anion exchange chromatography on Q-Sepharose, ion exchange chromatography by fast protein liquid chromatography (FPLC) on Mono Q and Mono S, and gel filtration by FPLC on Superdex 75. Two of the trypsin-chymotrypsin inhibitors were adsorbed on the first four types of chromatographic media. All three inhibitors have a molecular mass of 16 kDa as judged by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The trypsin inhibitory activity of the inhibitors was attenuated in the presence of the reducing agent dithiothreitol. The remaining inhibitor was unadsorbed on SP-Sepharose but adsorbed on Q-Sepharose, Mono Q and Mono S. The protease inhibitors did not exert any inhibitory effect on hepatoma (Hep G2) and breast cancer (MCF 7) cells or antifungal action toward Botrytis cinerea, Fusarium oxysporum and Mycosphaerella arachidicola. Two of the inhibitors slightly inhibited the activity of HIV-1 reverse transcriptase, with an IC50 in the millimolar range.
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PMID:Trypsin-chymotrypsin inhibitors from Vigna mungo seeds. 1927 41

A lectin has been isolated from seeds of the Phaseolus vulgaris cv. "Anasazi beans" using a procedure that involved affinity chromatography on Affi-gel blue gel, fast protein liquid chromatography (FPLC)-ion exchange chromatography on Mono S, and FPLC-gel filtration on Superdex 200. The lectin was comprised of two 30-kDa subunits with substantial N-terminal sequence similarity to other Phaseolus lectins. The hemagglutinating activity of the lectin was stable within the pH range of 1-14 and the temperature range of 0-80 degrees C. The lectin potently suppressed proliferation of MCF-7 (breast cancer) cells with an IC(50) of 1.3 microM, and inhibited the activity of HIV-1 reverse transcriptase with an IC(50) of 7.6 microM. The lectin evoked a mitogenic response from murine splenocytes as evidenced by an increase in [3H-methyl]-thymidine incorporation. The lectin had no antifungal activity. It did not stimulate nitric oxide production by murine peritoneal macrophages. Chemical modification results indicated that tryptophan was crucial for the hemagglutinating activity of the lectin.
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PMID:Purification and characterization of a lectin from Phaseolus vulgaris cv. (Anasazi beans). 1934 72

Effects of electromagnetic fields (EMFs) on the incidence of breast cancer (BC) have been proposed by a number of epidemiological studies. The molecular mechanism of the impact of EMFs on cells is not yet clear, although changes in gene expression have been reported in various cellular systems. In this investigation, the interference of low-frequency EMFs with the plasminogen activator system was examined in BC cells.MCF-7 BC cells from 2 different sources were exposed to highly homogeneous 50-Hz EMFs. Changes in gene expression were analyzed by reverse transcriptase-polymerase chain reaction.In MCF-7 cells exposed to 1.2 microT EMF expression of the urokinase plasminogen activator gene and of plasminogen-activator inhibitor-1 was markedly increased. The expression of the receptor for urokinase plasminogen activator was only marginally increased in 1 of the 2 tested cell lines and expression of the tissue plasminogen activator was at least slightly down-regulated in BC cells exposed to EMFs.EMFs may be able to increase the metastatic potential of breast tumors. The use of our newly established exposure system for EMFs may allow us to study the signaling processes involved in the induction of a metastatic phenotype of breast cancer cells.
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PMID:Exposure of mcf-7 breast cancer cells to electromagnetic fields up-regulates the plasminogen activator system. 1940 55

An 9.4-kDa antifungal peptide designated as campesin was isolated from seeds of the cabbage Brassica campestris. The isolation procedure involved affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Q-Sepharose and Mono S, and gel filtration on Superdex 75 and Superdex Peptide. The peptide was adsorbed on the first three chromatographic media. It exerted an inhibitory action on mycelial growth including Fusarium oxysporum and Mycosphaerella arachidicola, with an IC(50) of 5.1 microM and 4.4 microM, respectively. The peptide was characterized by remarkable thermostability and pH stability. It inhibited proliferation of HepG2 and MCF cancer cells with an IC(50) of 6.4 microM and 1.8 microM, and the activity of HIV-1 reverse transcriptase with an IC(50) of 3.2 microM. It demonstrated lysolecithin binding activity.
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PMID:Campesin, a thermostable antifungal peptide with highly potent antipathogenic activities. 1966 63

A dimeric 64-kDa hemagglutinin was isolated with a high yield from dried Phaseolus vulgaris cultivar "French bean number 35" seeds using a chromatographic protocol that involved Blue-Sepharose, Q-Sepharose, and Superdex 75. The yield was exceptionally high (1.1g hemagglutinin per 100g seed), which is around 10-85 times higher than other Phaseolus cultivars. Its N-terminal sequence resembled those of other Phaseolus hemagglutinins. The hemagglutinating activity of the hemagglutinin was stable in the pH range 6-8, and in the temperature range 0 degrees C-50 degrees C. It inhibited HIV-1 reverse transcriptase with an IC50 of 2microM. It suppressed mycelial growth in Valsa mali with an IC50 of 10microM. It inhibited proliferation of hepatoma HepG2 cells and breast cancer MCF-7 cells with an IC50 of 100 and 2microM, respectively. It had no antiproliferative effect on normal embryonic liver WRL68 cells.
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PMID:Isolation and characterization of a French bean hemagglutinin with antitumor, antifungal, and anti-HIV-1 reverse transcriptase activities and an exceptionally high yield. 1974 Jun 39

A hexameric 150-kDa lectin was isolated from dried Hibiscus mutabilis seeds using a chromatographic protocol that involved ion exchange chromatography on SP-Sepharose, and gel filtration on Superdex 75 and Superdex 200. The lectin was not adsorbed on SP-Sepharose and was eluted from the Superdex 75 column in the void volume. It was eluted in the first peak from Superdex 200. It was strongly adsorbed on DEAE-cellulose and Q-Sepharose and could not be easily desorbed. The hemagglutinating activity of the lectin, which was stable at pH 4-7 and up to 50 degrees C, could be inhibited by 25 mM galactonic acid. This is the first report of a galactonic acid-binding lectin. It potently inhibited HIV-1 reverse transcriptase with an IC(50) of 0.2 microM. It exhibited weak antiproliferative activity towards both hepatoma HepG2 cells (40% inhibition) and breast cancer MCF-7 cells (50% inhibition) at 100 microM concentration of the lectin. It did not inhibit mycelial growth of a number of fungi tested.
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PMID:Novel galactonic acid-binding hexameric lectin from Hibiscus mutabilis seeds with antiproliferative and potent HIV-1 reverse transcriptase inhibitory activities. 1995 5

A dimeric lectin with a molecular weight of 60 kDa and high hemagglutinating activity was isolated from dried cicadas. It was adsorbed on Q-Sepharose and unadsorbed on Affi-Gel Blue gel. Its hemagglutinating activity was stable up to 55 degrees C and between pH 2 and 13. The activity was inhibited by glucuronic acid and raffinose, K(+) ions, and Mg(2+) ions. Cicada lectin potently inhibited proliferation of HepG2 hepatoma and MCF 7 breast cancer cells, with an IC(50) value of 0.76 and 0.49 microM, respectively. It potently inhibited HIV-1 reverse transcriptase activity with an IC(50) of 0.36 microM but was devoid of mitogenic activity on spleen cells. Its N-terminal sequence exhibited slight similarity to a conserved hypothetical protein from Culex quinquefasciatus and a gene product from transcript GH19834-RA of Drosophila grimshawi, but there was no resemblance to lectins from other insects, including Drosophila, Sarcophaga, Glossina, and Aedes species.
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PMID:A novel lectin with highly potent antiproliferative and HIV-1 reverse transcriptase inhibitory activities from cicada (Cicada flammata). 1995 41


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