Abstract：
:The kinetics of methotrexate inhibition of dihydrofolate reductase from Neisseria gonorrhoeae have been investigated. Methotrexate was shown to be a tight-binding inhibitor (Kt = 13 pM) competitive with dihydrofolate. However, "stoichiometric" or "pseudoirreversible" inhibition could not be demonstrated. Progress curves of inhibited assays quickly attained steady state regardless of the order of substrate addition, indicating that methotrexate association and dissociation processes were rapid. Kinetic techniques were used to measure the rate of methotrexate dissociation from the enzyme-NADPH-methotrexate ternary complex. At 30 degrees, the first-order off-rate constant (koff) was calculated to be 0.56 min-1. This value is approximately 40-fold greater than the dissociation rate constant of methotrexate for Escherichia coli dihydrofolate reductase. At lower temperatures, progress curves of methotrexate-inhibited gonococcal enzyme assays displayed marked increases in both curvature and the time to reach steady state. At 9 degrees, the methotrexate dissociation rate was slow enough (koff = 0.04 min-1) so that initial velocities of the reaction could be measured, and under these conditions methotrexate inhibition was shown to be "stoichiometric".
journal_name
Biochem Pharmacoljournal_title
Biochemical pharmacologyauthors
Baccanari DP,Tansik RLdoi
10.1016/0006-2952(84)90579-3subject
Has Abstractpub_date
1984-07-01 00:00:00pages
2101-7issue
13eissn
0006-2952issn
1873-2968pii
0006-2952(84)90579-3journal_volume
33pub_type
杂志文章abstract：:Human immunodeficiency virus type 1 (HIV-1) is wholly dependent on its host cell for a variety of essential metabolites. Among the latter are the deoxynucleoside-5'-triphosphates (dNTPs) required for reverse transcription of the single-stranded RNA viral genome into double-stranded viral DNA. Since viral DNA synthesis...
journal_title：Biochemical pharmacology
pub_type： 杂志文章,评审
doi：10.1016/s0006-2952(97)00664-3
更新日期：1998-05-15 00:00:00
abstract：:Although it is known that the pathogenic mechanism of Helicobacter pylori involves the stimulated production of interleukin-8 (IL-8) as an inflammatory mediator, the details of the pathway remain unclear. The role of mitogen-activated protein kinase (MAPK) in IL-8 production by H. pylori has been examined in an in vit...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/s0006-2952(01)00628-1
更新日期：2001-06-15 00:00:00
abstract：:Dichlorodi[U-14C]phenyltrichloroethane ( [14C]DDT), incubated with rat hepatic microsomes and NADPH, produced reactive intermediates which covalently bound to microsomal protein and lipids. In atmospheric oxygen, DDT bound to microsomal protein; however, binding was increased up to approximately 70% by oxygen depletio...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(84)90483-0
更新日期：1984-01-15 00:00:00
abstract：:The mechanism of activation of microsomal glutathione transferase in isolated liver cells by diisapropylidene acetone (phorone) was investigated. Phorone (1 mM) causes a time-dependent increase (up to 2.6-fold) in the glutathione transferase activity of microsomes isolated from treated hepatocytes. Since phorone react...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(92)90269-o
更新日期：1992-01-22 00:00:00
abstract：:In order to clarify the mechanism of substance P (SP)-induced cortisol secretion from bovine adrenocortical (BAC) cells, protein synthesis at the early stage of SP-stimulation in BAC cells was investigated. Both SP and adrenocorticotropic hormone (ACTH) increased [3H]leucine uptake into BAC cells in a dose-dependent f...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(92)90537-s
更新日期：1992-10-06 00:00:00
abstract：:Imidazoline-like drugs are centrally-acting antihypertensive agents that inhibit the activity of the sympathetic nervous system by interacting with the alpha2-adrenoreceptor and also with a non-adrenergic imidazoline binding site called the imidazoline 1 receptor. Recently, these molecules were proposed to play an add...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2005.01.005
更新日期：2005-04-01 00:00:00
abstract：:We studied several steps of methionine metabolism in isolated rat hepatocytes both with and without the presence of a hepatotoxic agent (D-galactosamine). By use of selective labelling either on methyl or on carboxyl groups, we showed that intracellular methionine is used preferentially for the methylation of phosphol...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(86)90699-4
更新日期：1986-12-01 00:00:00
abstract：:In order to study the metabolism of benzo[a]pyrene (BP), it must be dissolved in an organic solvent vehicle for delivery to the tissue. We studied the effects of five organic solvent vehicles, i.e. dimethyl sulfoxide (DMSO), acetone, methanol, ethanol, and ethyl acetate, on benzo[a]pyrene hydroxylase activity and the ...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(86)90055-9
更新日期：1986-08-01 00:00:00
abstract：:Lipophilicity of camptothecins derivatives has been reported to improve the stability of the lactone ring and to favor rapid uptake and intracellular accumulation. Recently, a novel series of lipophilic camptothecins substituted at position 7 was developed, and gimatecan (ST1481) was selected for clinical development ...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2003.10.034
更新日期：2004-03-15 00:00:00
abstract：:The vasoactive urotensin-II (UII), a cyclic undecapeptide widely distributed in cardiovascular, renal and endocrine systems, specifically binds the UII receptor (UT receptor), a G protein-coupled receptor (GPCR). The involvement of this receptor in numerous pathophysiological conditions including atherosclerosis, hear...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2014.08.023
更新日期：2014-11-15 00:00:00
abstract：:We investigated the role played by monoclonal antibody defined classes of cytochrome P-450 in the metabolism of antipyrine, aminopyrine and theophylline. Two enzyme inhibitory monoclonal antibodies (MAb 1-7-1 and MAb 2-66-3) raised to two forms of cytochrome P-450 were used. Microsomes were prepared from the livers of...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(87)90604-6
更新日期：1987-07-15 00:00:00
abstract：:Cell based studies have suggested that the diabetes drug metformin may combine with the anaplastic lymphoma kinase receptor (ALK) inhibitor crizotinib to increase ALK positive lung cancer cell killing and overcome crizotinib resistance. We therefore tested metformin alone and in combination with crizotinib in vivo, by...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2020.114345
更新日期：2021-01-01 00:00:00
abstract：:Methotrexate (MTX) is a chemotherapy agent linked to cognitive deficits in cancer patients received chemotherapy treatment. MTX decreases cell proliferation in the hippocampus, which is concomitant with cognitive deficits in animal models. The present study aimed to investigate the disadvantages of MTX on cognition as...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2019.02.010
更新日期：2019-05-01 00:00:00
abstract：:β1-Adrenergic receptor (β1-AR) agonists and antagonists are widely used in the treatment of major cardiovascular diseases such as heart failure and hypertension. The β1-AR like other G protein-coupled receptors (GPCRs) are endocytosed in response to intense agonist activation. Recycling of the agonist-internalized β1-...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2016.09.011
更新日期：2016-11-15 00:00:00
abstract：:Purified ornithine decarboxylase (EC 4.1.1.17, ODC) transamidated with four putrescine moieties on four glutamine residues through the action of transglutaminase (EC 2.3.2.13, TGase) purified from guinea pig liver, when added to isolated rat liver nuclei, stoichiometrically increased the activity of RNA polymerase I (...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(82)90614-1
更新日期：1982-11-01 00:00:00
abstract：:Thyroid hormones play a role in the regulation of glutathione S-transferase (GST) expression. Here, co-cultures of rat hepatocytes with bile duct epithelial cells have been used to study the direct effects of both triiodothyronine (T3) and thyroxine (T4) on GST activities and proteins. Because T3 and T4 are poorly wat...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/s0006-2952(01)00557-3
更新日期：2001-05-01 00:00:00
abstract：:Boldine ([S]-2,9-dihydroxy-1,10-dimethoxyaporphine) has been shown to exert antioxidant and anti-inflammatory effects. The present study elucidated the protective effect of boldine on catecholamine-induced membrane permeability transition in brain mitochondria and viability loss in PC12 cells. Dopamine (200 microM) an...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/s0006-2952(01)00852-8
更新日期：2002-02-01 00:00:00
abstract：:The effect of oxidant stress produced by redox cycling of substituted 1,4-naphthoquinones on the activity of platelet (Na(+)-K+)ATPase and the active transport of serotonin (5-HT) was studied. 2-Methyl-1,4-naphthoquinone (menadione) produced a concentration-dependent (0-100 microM) and time-dependent (2-20 min) stimul...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(91)90203-h
更新日期：1991-03-15 00:00:00
abstract：:Sulfasalazine (SF) promotes remyelination and improves the outcome of multiple sclerosis (MS) patients. However, the underlining mechanism remains elusive. Here, we examined whether SF blocks microglia switching to a pro-inflammatory M1-like phenotype through a competing endogenous RNA (ceRNA) effects in cuprizone-ind...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2018.06.028
更新日期：2018-09-01 00:00:00
abstract：:Several hepatotoxic agents with varied chemical mechanisms of toxicity (acetaminophen, diquat, and CCl4) depress membrane calcium pumps and/or enhance the permeability of membranes to calcium. To probe the relevance of these findings to maintenance of calcium homeostasis after toxins in vivo, we measured the activity ...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(89)90016-6
更新日期：1989-09-15 00:00:00
abstract：:There is a strong association between tobacco smoking and the consumption of alcoholic beverages. When compared to the effects of either drug on its own, the combined use may lead to worsened outcomes, such as less successful quitting attempts and increased likelihood of developing mood disorders. Co-consumption most ...
journal_title：Biochemical pharmacology
pub_type： 杂志文章,评审
doi：10.1016/j.bcp.2017.06.113
更新日期：2017-11-15 00:00:00
abstract：:N-Trifluoroacetyladriamycin-14-valerate (AD 32), a lipophilic, DNA non-binding analog of Adriamycin (ADR), was found to be a potent inhibitor of the membrane-bound enzyme, protein kinase C (PKC). PKC was isolated and purified from human leukemia ML-1 cells, and the enzyme activity was shown to be activated by the tumo...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(92)90254-g
更新日期：1992-02-18 00:00:00
abstract：:It has been reported that chelerythrine chloride, a benzophenanthridine alkaloid, with a wide variety of biologic effects stimulates the phosphorylation of an approximately 20 kDa protein present in the mitochondrial fraction of the rat retina. It has also been shown previously that both the serine and threonine resid...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(96)00202-x
更新日期：1996-07-26 00:00:00
abstract：:Multidrug resistance-associated protein (MRP-1/ABCC1) transports a wide range of therapeutic agents and may play a critical role in the development of multidrug resistance (MDR) in tumor cells. However, the regulation of MRP-1 remains controversial. To explore whether miRNAs are involved in the regulation of MRP-1 exp...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2009.10.017
更新日期：2010-03-15 00:00:00
abstract：:Macrophage migration inhibitory factor (MIF) plays some pivotal roles in innate immunity and inflammation. Ursolic acid (UA), an anti-inflammatory triterpene carboxylic acid, was recently reported to induce the release of pro-inflammatory mediators in resting macrophages (Mvarphi). We investigated the effects of UA on...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2005.08.008
更新日期：2005-11-15 00:00:00
abstract：:Glyburide is a second-generation sulfonylurea hypoglycemic drug used for the treatment of select women with pregestational and gestational diabetes mellitus (GDM). In vitro and in vivo investigations demonstrated its very low transplacental transfer to the fetal circulation. However, the factors influencing its low tr...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2006.05.019
更新日期：2006-08-28 00:00:00
abstract：:The influence of various concentrations of ferrous iron and ascorbate on in vitro peroxidation and drug binding of diverse membrane preparations (cerebral cortex and liver) was studied. Peroxidation was not simply dose-related to ascorbate and ferrous iron, but a complex relationship between iron and ascorbate when ad...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(95)02058-6
更新日期：1995-11-27 00:00:00
abstract：:We have studied the effects of thimerosal, a mercurial compound extensively used as a preservative, as well as other sulfhydryl reagents (e.g. p-hydroxymercurybenzoate, hydrogen peroxide, bromophenacyl bromide, and mercuric chloride) on Ca2+ homeostasis and the redox status of sulfhydryl groups in thymus lymphocytes. ...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/s0006-2952(94)00401-3
更新日期：1995-01-18 00:00:00
abstract：:Idiopathic pulmonary fibrosis (IPF) involves infiltration of leucocytes, pulmonary injury, fibrosis and resulting pulmonary dysfunction. Myofibroblasts and transforming growth factor (TGF)-beta1 have been suggested to play a major role in the pathology and the myofibroblasts are derived from both lung epithelial cells...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/j.bcp.2010.05.025
更新日期：2010-09-15 00:00:00
abstract：:The serine esterase inhibitor diisopropyl fluorophosphate (DFP) had been reported previously to inhibit IgE-dependent histamine release. Recently, it has been demonstrated that lower concentrations of DFP enhance IgE-dependent histamine release and inhibit desensitization. This manuscript describes the abilities of se...
journal_title：Biochemical pharmacology
pub_type： 杂志文章
doi：10.1016/0006-2952(86)90686-6
更新日期：1986-12-01 00:00:00
