Abstract:
:The plasma membrane of cells contains enzymes whose active sites face the external medium rather than the cytoplasm. The activities of these enzymes, referred to as ectoenzymes, can be measured using living cells. In this work we describe the ability of living promastigotes of Leishmania amazonensis to hydrolyze extracellular ATP. In these intact parasites whose viability was assessed before and after the reactions by motility and by trypan blue dye exclusion, there was a low level of ATP hydrolysis in the absence of any divalent metal (5.39 +/- 0.71 nmol P(i)/h x 10(7) cells). The ATP hydrolysis was stimulated by MgCl(2) and the Mg-dependent ecto-ATPase activity was 30.75 +/- 2.64 nmol P(i)/h x 10(7) cells. The Mg-dependent ecto-ATPase activity was linear with cell density and with time for at least 60 min. The addition of MgCl(2) to extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. At 5 mM ATP, half-maximal stimulation of ATP hydrolysis was obtained with 1.21 mM MgCl(2). This stimulatory activity was also observed when MgCl(2) was replaced by MnCl(2), but not by CaCl(2) or SrCl(2). The apparent K(m) for Mg-ATP(2-) was 0.98 mM and free Mg(2+) did not increase the ecto-ATPase activity. In the pH range from 6.8 to 8.4, in which the cells were viable, the acid phosphatase activity decreased, while the Mg(2+)-dependent ATPase activity increased. This ecto-ATPase activity was insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin A(1), ouabain, furosemide, vanadate, molybdate, sodium fluoride, tartrate, and levamizole. To confirm that this Mg-dependent ATPase was an ecto-ATPase, we used an impermeant inhibitor, 4,4'-diisothiocyanostylbene 2',2'-disulfonic acid as well as suramin, an antagonist of P(2) purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg(2+)-dependent ATPase activity in a dose-dependent manner. A comparison between the Mg(2+)-dependent ATPase activity of virulent and avirulent promastigotes showed that avirulent promastigotes were less efficient than the virulent promastigotes in hydrolyzing ATP.
journal_name
Arch Biochem Biophysjournal_title
Archives of biochemistry and biophysicsauthors
Berrêdo-Pinho M,Peres-Sampaio CE,Chrispim PP,Belmont-Firpo R,Lemos AP,Martiny A,Vannier-Santos MA,Meyer-Fernandes JRdoi
10.1006/abbi.2001.2384subject
Has Abstractpub_date
2001-07-01 00:00:00pages
16-24issue
1eissn
0003-9861issn
1096-0384pii
S0003-9861(01)92384-7journal_volume
391pub_type
杂志文章abstract::The enzyme ketol acid reductoisomerase catalyzes the second common reaction in the biosynthesis of the branched chain amino acids. The reaction is complex as an alkyl migration and a ketone reduction apparently occur as separate steps during the conversion of acetolactate to 2,3-dihydroxy-3-methylbutyrate. This paper ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(92)90710-e
更新日期:1992-05-01 00:00:00
abstract::In the Escherichia coli class Ia ribonucleotide reductase (RNR), the best characterized RNR, there is no spectroscopic evidence for the existence of the postulated catalytically essential thiyl radical (R-S(*)) in the substrate binding subunit R1. We report first results on artificially generated thiyl radicals in R1 ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.2001.2658
更新日期:2002-01-01 00:00:00
abstract::Radiotherapy plays a limited role in the treatment of hepatocellular carcinoma (HCC) due to the development of resistance. Therefore, further investigation of underlying mechanisms involved in HCC radioresistance is warranted. Increasing evidence shows that long non-coding RNAs (linc-RNAs) are involved in the patholog...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2018.03.018
更新日期:2018-05-01 00:00:00
abstract::Appropriate dietary interventions may reduce the potentially damaging effects of free radicals generated during metabolism and various physiological conditions. We have investigated the effects of dietary vitamins C, E, beta-carotene, or selenium (Se) on the activity of endogenous antioxidant enzymes and respiratory c...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.2001.2548
更新日期:2001-10-15 00:00:00
abstract::In an effort to better understand the Ah receptor nuclear translocator (Arnt)-dependent signaling mechanisms, we employed a phage display system to identify Arnt-interacting peptides. Human liver cDNA library was utilized to screen for Arnt-interacting peptides using an Arnt construct fused to thioredoxin (TH-ArntCDel...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2005.06.026
更新日期:2005-09-01 00:00:00
abstract::Flavopiridol has been shown to induce cell cycle arrest and apoptosis in various tumor cells in vitro and in vivo. Using immobilized flavopiridol, we identified glycogen phosphorylases (GP) from liver and brain as flavopiridol binding proteins from HeLa cell extract. Purified rabbit muscle GP also bound to the flavopi...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.2000.2220
更新日期:2001-02-15 00:00:00
abstract::DNA damage has been postulated as a mechanism of neuronal death in Parkinson's disease (PD). In the present study, genomic DNA was isolated from eight brain regions (frontal, temporal, and occipital cortex, hippocampus, caudate/putamen, thalamus, cerebellum, and midbrain) from five neuropathologically confirmed cases ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2006.02.018
更新日期:2006-05-15 00:00:00
abstract::The presence of multiple proteases in the culture filtrate of Streptomyces moderatus was detected. After preliminary purification by ammonium sulfate precipitation and decolorization using DEAE-cellulose, the fractionation of various proteases was carried out using CM-trisacryl cation-exchange chromatography. By this ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(87)90582-0
更新日期:1987-09-01 00:00:00
abstract::Activation of the NLRP3 inflammasome plays an important role in high glucose- induced endothelial dysfunction in patients with type 2 diabetes mellitus (T2DM). Dulaglutide, a newly developed glucagon-like peptide-1 receptor (GLP-1R) agonist, has been approved for the management of T2DM. In the current study, we aimed ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2019.07.008
更新日期:2019-08-15 00:00:00
abstract::Polyunsaturated fatty acids (PUFAs) are reported to exert beneficial effects in Alzheimer's disease. Some PUFAs are known to reduce amyloid-beta (Aβ) toxicity by promoting its degradation and clearance. Studies on the direct interactions of PUFAs with Aβ peptides are limited and contradictory. In this study, we report...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2018.12.027
更新日期:2019-03-15 00:00:00
abstract::Cellular distribution in rat livers of the mannan-binding protein, a liver lectin specific for mannose and N-acetylglucosamine was investigated. Estimation of mannan binding activity of isolated cells demonstrated that more than 99% of the mannan binding activity recovered from whole livers was derived from hepatocyte...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(83)90552-0
更新日期:1983-04-15 00:00:00
abstract::Catalytic activity of ISWI chromatin remodelers, which regulate nucleosome positioning on the DNA, depends on interactions of the putative acidic patch in ISWI helicase domain with the N-termini of nucleosomal H4--such, that removal of H4 termini abolishes ISWI remodeling. Acetylation of H4 termini is also known to di...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2015.12.002
更新日期:2016-02-01 00:00:00
abstract::Sensitive assays were developed for long chain and very long chain fatty acid oxidation in human skin fibroblast homogenates. Stearic and lignoceric acids were degraded by the fibroblasts by the beta-oxidation pathway. The cofactor requirements for stearic and lignoceric acid beta-oxidation were very similar but not i...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(86)90714-9
更新日期:1986-10-01 00:00:00
abstract::We investigated the role of free radicals in hemoglobin (Hb) oxidation and denaturation. To generate free radicals, we used two azocompounds, the hydrophilic 2,2'-azobis(2-amidinopropane hydrochloride and the hydrophobic 2,2'-azobis(2,4-dimethylvaleronitrile) and a drug of the quinone family, phenazine methosulfate. T...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1993.1205
更新日期:1993-04-01 00:00:00
abstract::Three protein disulfide reductases of the thioredoxin superfamily from the industrially important Gram-positive Lactococcus lactis (LlTrxA, LlTrxD and LlNrdH) are compared to the "classical" thioredoxin from Escherichia coli (EcTrx1). LlTrxA resembles EcTrx1 with a WCGPC active site motif and other key residues conser...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2014.09.010
更新日期:2014-12-15 00:00:00
abstract::Serine is an essential amino acid for the lectin-mediated transformation of human peripheral blood lymphocytes due to the inability of this cell to synthesize sufficient quantities via either the phosphorylated pathway or by reversal of the serine hydroxymethyltransferase reaction to meet the metabolic demands. The le...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(85)90627-7
更新日期:1985-01-01 00:00:00
abstract::A recent note from our laboratory reported that L-band (1.2 GHz) electron paramagnetic resonance spectroscopy can be utilized in detecting the formation of Cr(V) intermediates from chromate-treated whole mice. Since Cr(V) is thought to be one of the key species in the mechanism of chromate's toxicity, we carried out a...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1995.0006
更新日期:1995-10-20 00:00:00
abstract::Inactivation of the von Hippel-Lindau (VHL) tumor suppressor is associated with renal carcinoma, hemangioblastoma and pheochromocytoma. The VHL protein is a component of a ubiquitin ligase complex that ubiquitinates and degrades hypoxia inducible factor-α (HIF-α). Degradation of HIF-α by VHL is proposed to suppress tu...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2011.12.023
更新日期:2012-02-15 00:00:00
abstract::Peroxisome proliferator-activated receptor alpha (PPARα) has been implicated in the pathogenesis of cardiac hypertrophy, although its mechanism of action remains largely unknown. To determine the effect of PPARα activation on endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy and explore its molecular mechanisms, w...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2011.11.024
更新日期:2012-02-01 00:00:00
abstract::Affinity columns prepared by immobilizing monoclonal antibodies that specifically recognize the Lea or the Leb blood group antigens can be used for analytical or preparative isolation of oligosaccharides with the corresponding reactivities. The number of immobilized functional antibody combining sites on a column and ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(88)90586-3
更新日期:1988-07-01 00:00:00
abstract::Human lactase-phlorizin hydrolase [EC 3.2.1.23-3.2.1.62] is a disaccharidase located in the microvillus membrane of small intestinal epithelial cells. The enzyme is synthesized as a precursor protein in the endoplasmic reticulum and in addition to being glycosylated is subsequently proteolytically processed to the mat...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1995.9952
更新日期:1995-11-10 00:00:00
abstract::Recombinant ethanolamine ammonia-lyase from S. typhimurium has been overexpressed and purified in large quantities by a simple procedure. The molecular weight of the native enzyme is about 480 kDa, and it contains two active sites/molecule as shown by kinetic studies and by titration with CNCbl. Analysis by sodium dod...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(92)90135-j
更新日期:1992-04-01 00:00:00
abstract::Cold plasma is partly ionized non-thermal plasma generated at atmospheric pressure. It has been recognized as an alternative approach in medicine for sterilization of wounds, promotion of wound healing, topical treatment of skin diseases with microbial involvement and treatment of cancer. Cold plasma used in wound the...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/j.abb.2016.03.033
更新日期:2016-09-01 00:00:00
abstract::The effects of GSH on the autoxidation of the fava bean pyrimidine aglycones, divicine and isouramil, and on acid-hydrolyzed vicine (provisional identification 2-amino-4,5,6-trihydroxypyrimidine) have been studied. GSH alone promoted redox cycling of each compound, with concomitant GSH oxidation and H2O2 production. I...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(89)90295-6
更新日期:1989-06-01 00:00:00
abstract::Immunological cross-reactivities between isolated subunits of the scorpion Androctonus australis (Aa) and of the horseshoe crab Limulus polyphemus (Lp) hemocyanins were studied using subunit-specific antibodies prepared through immunoadsorption to pure immobilized subunits. Rocket immunoelectrophoreses of the various ...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(83)90623-9
更新日期:1983-06-01 00:00:00
abstract::Progress of mutagenesis studies on the relation of the structure of Na+/K+-ATPase to its reaction mechanism has been impeded by the paucity of information on the properties of small amounts of impure recombinant enzyme obtained in the currently available expression systems, and the uncertainty of whether expression in...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1996.0237
更新日期:1996-06-01 00:00:00
abstract::Production of hydroxyl radicals (HO.) by substrate-supplemented beef heart submitochondrial particles was studied by electron paramagnetic resonance in conjunction with the spin trap 5,5'-dimethyl-1-pirroline-N-oxide (DMPO). Supplementation of submitochondrial particles with NADH or succinate in the presence of antimy...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1995.1122
更新日期:1995-02-01 00:00:00
abstract::Caffeic acid O-methyltransferase (COMT) is one of a group of proteins present in alfalfa cell cultures which can be photoaffinity labeled with S-adenosyl-L-[methyl-3H]methionine. The enzyme was purified to homogeneity from elicitor-treated suspension cultures and shown to exist as an active monomer of subunit Mr 41,00...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1016/0003-9861(91)90492-2
更新日期:1991-06-01 00:00:00
abstract::Lipoxygenase is suggested to be involved in the early event of atherosclerosis by inducing plasma low-density lipoprotein (LDL) oxidation in the subendothelial space of the arterial wall. Since flavonoids such as quercetin are recognized as lipoxygenase inhibitors and they occur mainly in the glycoside form, we assess...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.1997.0455
更新日期:1998-01-15 00:00:00
abstract::Cofactor and tryptophan accessibility of the 65-kDa form of rat brain glutamate decarboxylase (GAD) was investigated by fluorescence quenching measurements using acrylamide, I-, and Cs+ as the quenchers. Trp residues were partially exposed to solvent. I- was less able and Cs+ was more able to quench the fluorescence o...
journal_title:Archives of biochemistry and biophysics
pub_type: 杂志文章
doi:10.1006/abbi.2001.2466
更新日期:2001-08-15 00:00:00