共查询到20条相似文献,搜索用时 31 毫秒
1.
R Cramer G Meyer M Loche M Robert-Gero 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1980,291(7):633-636
BHK21 cells transformed by wild type or Ts3 mutant polyoma virus contain an inhibitor of polyoma virus replication when grown at permissive (36 degrees C) as well as non-permissive temperature (39 +/- 0.5 degrees C). Cells transformed by the Tsa mutant contain the inhibitor at the permissive but not at the non-permissive temperature. The inhibitor reappears in the latter cells however, upon shift from the non-permissive to the permissive temperature. If a reversible protein inhibitor (methionyl-adenylate, reversible inhibitor of the aminoacyl-t-RNA synthetase) is applied during the temperature shift experiments, the inhibitor does not reappear indicating that new protein synthesis is required for the recovery of its activity. 相似文献
2.
M Bounias 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1977,285(3):261-264
The alpha-glucosidasic activity of emerging honeybees haemolymph is submitted to a feed-back inhibition by glucose, according to a mechanism of the "K" type (competitive). The "resulting affinity-constant" (measured in the presence of the enzyme both with substrate and inhibitor) is linear function of the inhibitor concentration. The affinity constants between enzyme and pure substrate on one hand, and between enzyme and pure inhibitor on the other hand, were determined by means of this relation, which led to respectively equivalent values after determinations under in vitro or in vivo inhibitions. 相似文献
3.
Summary Chicken spinal cord adenosine triphosphatases (both Na+, K+ stimulated and ouabain insensitive) were inhibited by tri-o-tolyl phosphate (TOTP, a neurotoxic organophosphate which is not a cholinesterase inhibitor) and mevinphos (a non-neurotoxic compound but inhibitor of cholinesterases). The inhibition was concentration and time dependent, with an initial rapid drop in activity followed by a gradual exponential decline. 相似文献
4.
Summary The inhibition of monoamine oxidase (MAO) activity by d-amphetamine was measured in homogenates of cat superior cervical ganglion and nictitating membrane, using tyramine (TM) and noradrenaline (NA) as substrates. In both tissues, d-amphetamine was shown to be a competitive inhibitor of the oxidation of TM. The Ki for d-amphetamine, as a MAO inhibitor, was lower in the ganglia than in the peripheral nerve endings.Supported by a Contract from the National Research Council of Argentina (CONICET) (Res. 67/79). 相似文献
5.
F. E. Dorer J. M. Stewart J. W. Ryan 《Cellular and molecular life sciences : CMLS》1978,34(11):1436-1436
Summary Arg-Pro-Pro-Gly-Phe, the N-terminal pentapeptide of bradykinin, is not an inhibitor of angiotensin-converting enzyme and is not hydrolyzed by the enzyme. Arg-Pro-Pro, the N-terminal tripeptide is a relatively potent (IC50=2.3×106 M) inhibitor but its higher homolog, Gly-Arg-Met-Lys-Arg-Pro-Pro is not an inhibitor of angiotensin-converting enzyme.This work was supported in part by grants from the US Public Health Service (HL 18415, HL 15691, HL 19764) and the John A. Hartford Foundation, Inc., and by the Medical Research Service of the Veterans Administration. 相似文献
6.
Protein kinases mediate nitric oxide-induced apoptosis in the insect cell line IPLB-LdFB 总被引:2,自引:0,他引:2
The involvement of protein kinases (PKA, PKC and PKB) in nitric oxide (NO)-induced apoptosis with sodium nitroprusside plus
N-acetyl-L-cysteine in the IPLB-LdFB cell line from the insect Lymantria dispar was investigated. The presence of protein kinase-like molecules was demonstrated by western blot analysis. The role of the
kinases in programmed cell death was analysed in cytofluorimetric experiments by incubating the insect cells with H-89 (a
specific inhibitor of PKA), calphostin C (an inhibitor of PKC) or wortmannin (an inhibitor of phosphatidylinositol 3-kinase).
The results show that PKA is correlated with the induction and PKC and PKB with the prevention of NO-induced insect cell death.
Moreover, NO-induced apoptosis involves the release of cytochrome c.
Received 15 March 2002; accepted 25 March 2002 相似文献
7.
Quercetin is an effective inhibitor of human myeloperoxidase (MPO) activity, both with purified enzyme (IC50 = 3.5 microM) and in a system using stimulated human neutrophils. Quercetin is significantly more potent than three other related compounds (rutin, rutin sulfate and troxerutin) and than methimazole, a previously-known myeloperoxidase inhibitor. The inhibitory activity of quercetin is of the competitive type. Moreover, quercetin is directly able to scavenge hypochlorous acid (HOCl), a chlorinated species generated by the MPO/H2O2/Cl- system. 相似文献
8.
Ornithine decarboxylase (ODC), S-adenosyl-L-methionine decarboxylase (AMDC) and arginine decarboxylase (ADC) activities were detected for the first time in extracts of Mycobacterium bovis (BCG). All the decarboxylases differed from corresponding known bacterial decarboxylases in that: a) ODC did not require GTP for activity; b) ODC was not inhibited by any known inhibitor of bacterial ODCs; c) AMDC and ADC did not require Mg2+-ion for activity and were not markedly inhibited by any known inhibitor of the decarboxylases of other bacteria. 相似文献
9.
Summary Ornithine decarboxylase (ODC), S-adenosyl-L-methionine decarboxylase (AMDC) and arginine decarboxylase (ADC) activities were detected for the first time in extracts ofMycobacterium bovis (BCG). All the decarboxylases differed from corresponding known bacterial decarboxylases in that: a) ODC did not require GTP for activity; b) ODC was not inhibited by any known inhibitor of bacterial ODCs; c) AMDC and ADC did not require Mg2+-ion for activity and were not markedly inhibited by any known inhibitor of the decarboxylases of other bacteria. 相似文献
10.
S. K. Bhatacharya S. N. Mukhopadhyay P. K. Debnath A. K. Sanyal 《Cellular and molecular life sciences : CMLS》1976,32(7):907-908
Summary PGE1 potentiated, while diclofenac, a prostaglandin synthesis inhibitor, antagonized hexobarbitone hypnosis in rats. PGE1-induced potentiation of hexobarbitone sleep was inhibited by a 5HT synthesis inhibitor and by a 5HT receptor blocker, suggesting that this potentiation is 5HT mediated.Acknowledgment. The gift of the following drugs are gratefully acknowledged: PGE1 (Dr.J. E. Pike, Upjohn), diclofenac (Ciba-Geigy), methysergide (Sandoz) and hexobarbitone (Bayer). 相似文献
11.
Christian Feißt Carlo Pergola Marija Rakonjac Antonietta Rossi Andreas Koeberle Gabriele Dodt Marika Hoffmann Christina Hoernig Lutz Fischer Dieter Steinhilber Lutz Franke Gisbert Schneider Olof Rådmark Lidia Sautebin Oliver Werz 《Cellular and molecular life sciences : CMLS》2009,66(16):2759-2771
We previously showed that, in vitro, hyperforin from St. John’s wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses
a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B4 formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition
of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished
in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover,
hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation
in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together,
hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness
in vivo. 相似文献
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15.
The plasmin–antiplasmin system plays a key role in blood coagulation and fibrinolysis. Plasmin and α2-antiplasmin are primarily responsible for a controlled and regulated dissolution of the fibrin polymers into soluble fragments.
However, besides plasmin(ogen) and α2-antiplasmin the system contains a series of specific activators and inhibitors. The main physiological activators of plasminogen
are tissue-type plasminogen activator, which is mainly involved in the dissolution of the fibrin polymers by plasmin, and
urokinase-type plasminogen activator, which is primarily responsible for the generation of plasmin activity in the intercellular
space. Both activators are multidomain serine proteases. Besides the main physiological inhibitor α2-antiplasmin, the plasmin–antiplasmin system is also regulated by the general protease inhibitor α2-macroglobulin, a member of the protease inhibitor I39 family. The activity of the plasminogen activators is primarily regulated
by the plasminogen activator inhibitors 1 and 2, members of the serine protease inhibitor superfamily. 相似文献
16.
The intracellular signaling pathways mediating the nuclear exclusion of the androgen receptor (AR) by melatonin were evaluated
in PC3 cells stably transfected with the AR. The melatonin-induced nuclear exclusion of the AR by melatonin (100 nM, 3 h)
was blocked by LY 83583 (an inhibitor of guanylyl cyclases). 8-Bromo-cGMP (a cell-permeable cGMP analog), mimicked the effect
of melatonin, as did ionomycin (a calcium ionophore) and PMA [an activator of protein kinase C (PKC)], and their effects were
blocked by GF-109203X (a selective PKC inhibitor). BAPTA (an intracellular calcium chelator) blocked the effects of melatonin
and 8-bromo-cGMP but not of PMA. Inhibition or activation of the protein kinase A pathway did not affect basal or melatonin-mediated
AR localization. We conclude that the melatonin-mediated rise in cGMP elicits AR nuclear exclusion via a pathway involving
increased intracellular calcium and PKC activation. These results define a novel signaling pathway that regulates AR localization
and androgen responses in target cells.
Received 31 July 2001; received after revision 18 September 2001; accepted 30 October 2001 相似文献
17.
Larsson LI 《Cellular and molecular life sciences : CMLS》2004,61(19-20):2624-2631
Binding of growth factors to cell surface receptors activates protein tyrosine kinases (PTKs) that initiate cascades of downstream signaling events including the mitogen-activated protein (MAP) kinase cascade. This study reports that the PTK inhibitor AG 879 inhibits proliferation of human breast cancer cells through an effect involving inhibition of MAP kinase activation, but which cannot be explained by effects of AG 879 on its known PTK targets. Instead, AG 879 markedly inhibits expression of the RAF-1 gene, which encodes an upstream MAP kinase kinase kinase. Additionally, expression of HER-2, but not of other genes tested, is inhibited by this compound. These novel effects have to be considered when using AG 879 as a TRK-A and HER-2 inhibitor but may have useful therapeutic implications. 相似文献
18.
Barbara Wünschmann-Henderson T. Astrup 《Cellular and molecular life sciences : CMLS》1978,34(10):1288-1289
Summary The production of tissue plasminogen activator (TPA) in rat tongue organ cultures is strongly inhibited by low concentrations of the protein synthesis inhibitor cycloheximide. TPA production is fully resumed after the removal of cycloheximide from the culture medium.This study was supported by a USPHS grant (HE-05050) from the National Heart and Lung Institute. 相似文献
19.
B. Pellegrini-Quarantotti E. Paglietti A. Bonanni M. Petta G. L. Gessa 《Cellular and molecular life sciences : CMLS》1979,35(4):524-525
Summary Naloxone, a specific inhibitor of opioid receptors, lowers ejaculation threshold in the male rat coupled with receptive females.This study was sponsored by grant from Tecnofarmaci S.p.A.-Pomezia-Roma (Italy). Naloxone was kindly offered by Salars, Como (Italy) 相似文献
20.
Treatment 20 min beforehand with an inhibitor of nitric oxide (NO) synthesis, NW-nitro-l-arginine methyl ester (L-NAME) (12.5, 25, 50 or 100 mg/kg, s.c.), dose-dependently intensified gastric glandular mucosal ulceration produced by cold-restraint stress. Hexamethonium (20 mg/kg) or atropine (1 mg/kg) pretreatment s.c. 20 min before stress strongly antagonised stress-evoked ulceration, as well as the ulcer-potentiating effects of L-NAME when either cholinoceptor antagonist was given concurrently with the NO inhibitor. Stress-induced mast cell degranulation was not worsened by L-NAME pretreatment. The findings suggest that NO could confer partial protection against stress-induced gastric ulcer formation; its activity is triggered off by the ulcerogenic mechanism of stress. 相似文献