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Sigma receptors are small membrane proteins implicated in a number of pathophysiological conditions, including drug addiction, psychosis, and cancer; thus, small molecule inhibitors of sigma receptors have been proposed as potential pharmacotherapeutics for these diseases. We previously discovered that endogenous monochain N-alkyl sphingolipids, including d-erythro-sphingosine, sphinganine, and N,N-dimethylsphingosine, bind to the sigma-1 receptor at physiologically relevant concentrations [Ramachandran, S., et al. (2009) Eur. J. Pharmacol. 609, 19-26]. Here, we investigated several N-alkylamines of varying chain lengths as sigma receptor ligands. Although the K(I) values for N-alkylamines were found to be in the micromolar range, when N-3-phenylpropyl and N-3-(4-nitrophenyl)propyl derivatives of butylamine (1a and 1b, respectively), heptylamine (2a and 2b, respectively), dodecylamine (3a and 3b, respectively), and octadecylamine (4a and 4b, respectively) were evaluated as sigma receptor ligands, we found that these compounds exhibited nanomolar affinities with both sigma-1 and sigma-2 receptors. A screen of high-affinity ligands 2a, 2b, 3a, and 3b against a variety of other receptors and/or transporters confirmed these four compounds to be highly selective mixed sigma-1 and sigma-2 ligands. Additionally, in HEK-293 cells reconstituted with K(v)1.4 potassium channel and the sigma-1 receptor, these derivatives were able to inhibit the outward current from the channel, consistent with sigma receptor modulation. Finally, cytotoxicity assays showed that 2a, 2b, 3a, and 3b were highly potent against a number of cancer cell lines, demonstrating their potential utility as mixed sigma-1 and sigma-2 receptor anticancer agents. 相似文献
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《Journal of biological standardization》1986,14(2):103-109
The recovery of poliovirus D-antigen after virus inactivation was studied for two inactivating agents (β-propiolactone and formalin) using the three poliovirus types (Sabin types 1, 2 and 3). With β-propiolactone (BPL), D-antigen recoveries were high (88, 88 and 60%, respectively) but were significantly less when formalin was used (22, 15 and 25%). β-Propiolactone inactivated virus was purified, combined with Freund's adjuvant and used to hyperimmunize rabbits. High titres (50 000–200 000) of specific neutralizing antibody were obtained. 相似文献
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Elke Heremans Evelien Nackaerts Griet Vervoort Sanne Broeder Stephan P. Swinnen Alice Nieuwboer 《PloS one》2016,11(2)
Background
Patients with Parkinson’s disease (PD) and freezing of gait (FOG) suffer from more impaired motor and cognitive functioning than their non-freezing counterparts. This underlies an even higher need for targeted rehabilitation programs in this group. However, so far it is unclear whether FOG affects the ability for consolidation and generalization of motor learning and thus the efficacy of rehabilitation.Objective
To investigate the hallmarks of motor learning in people with FOG compared to those without by comparing the effects of an intensive motor learning program to improve handwriting.Methods
Thirty five patients with PD, including 19 without and 16 with FOG received six weeks of handwriting training consisting of exercises provided on paper and on a touch-sensitive writing tablet. Writing training was based on single- and dual-task writing and was supported by means of visual target zones. To investigate automatization, generalization and retention of learning, writing performance was assessed before and after training in the presence and absence of cues and dual tasking and after a six-week retention period. Writing amplitude was measured as primary outcome measure and variability of writing and dual-task accuracy as secondary outcomes.Results
Significant learning effects were present on all outcome measures in both groups, both for writing under single- and dual-task conditions. However, the gains in writing amplitude were not retained after a retention period of six weeks without training in the patient group without FOG. Furthermore, patients with FOG were highly dependent on the visual target zones, reflecting reduced generalization of learning in this group.Conclusions
Although short-term learning effects were present in both groups, generalization and retention of motor learning were specifically impaired in patients with PD and FOG. The results of this study underscore the importance of individualized rehabilitation protocols. 相似文献5.
Methyl 2,3-anhydro-4,6-O-benzylidene-3-C-nitro-β-d-allopyranoside (1), as well as its β-d-manno (2) and α- d-manno (3) isomers, reacted with dimethylamine to give the same, crystalline 3-(dimethylamino) adduct (4) of 1,5-anhydro-4,6-O-benzylidene-2-deoxy-2-(dimethylamino)-d-erythro-hex-1-en-3-ulose (5). The enulose 5 was obtained from 4 by the action of silica gel. Similarly, the β-d-gulo (6) and α-d-talo (7) stereoisomers of 1–3 afforded a 3-(dimethylamino) adduct (8) of the d-threo isomer (9) of 5. Reaction of dimethylamine with 5,6-anhydro-1,2-O-isopropylidene-6-C-nitro-α-d-glucofuranose (10) yielded a mixture of two diastereoisomeric (possibly anometic at C-6) 5-deoxy-5-(dimethylamino)-1,2-O-isopropylideric-α-d-hexodialdo-1,4:6,3-difuranoses (11). The β-glycoside 1 and the α-glycoside 3 reacted with methylmagnesium iodide to produce methyl 4,6-O-benzylidene-3-deoxy-3-C-methyl-3-(N-hydroxy-N-methylamino)-β- and -α-d-hexopyranosides (12) and (13), respectively; both products had the 1,2-trans configuration, but their configurations at the quaternary center C-3 have not been determined. 相似文献
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The effects of cellulose on the production and stimulation of β-transglycosylase were studied. The β-transglycosylase of Trichoderma longibrachiatum was produced specifically in the presence of cellulose in Czapeck-Dox medium containing sucrose as a sole carbon source. The enzyme activity was stimulated by the addition of cellulose in the reaction mixture, where the transfer reaction product (a water-insoluble glucan) was apparently synthesized on the surface of the added cellulose fibers.The hyphal wall fraction of the fungus had the same stimulatory effect on β-transglycosylase as the cellulose fibers. A cellulose-like material in this fraction was found by partial acid hydrolysis and gas chromatography. Cellotriose was the smallest substrate effective for the synthesis of a water-insoluble glucan in the presence of cellulose by the β-transglycosylase, though a significant amount of glucan could not be synthesized without the addition of cellulose. 相似文献
8.
Ying Zhang Ke Ren Zhiyao He Huili Li Tong Chen Yi Lei Shan Xia Gu He Yongmei Xie Yu Zheng Xiangrong Song 《Carbohydrate polymers》2013
Glaucoma is an accumulative optic neuropathy resulted from increasing intraocular pressure. Brinzolamide (BRZ) is a kind of carbonic anhydrase inhibitors for glaucoma treatment. In this study, brinzolamide-hydroxypropyl-β-cyclodextrin (BRZ-HP-β-CD) inclusion complex was prepared by solvent evaporation method to improve the solubility of BRZ and enhance the therapeutic effect of BRZ. The formation of the inclusion complex was confirmed by Fourier transform infrared spectroscopy, differential scanning calorimeter and nuclear magnetic resonance spectroscopy. The solubility of BRZ increased about 10-fold after the formation of the BRZ-HP-β-CD inclusion complex. The in vitro corneal accumulative permeability of the inclusion complex increased 2.91-fold compared to the commercial available formulation (AZOPT®). In addition, BRZ-HP-β-CD inclusion complex (0.5% BRZ) had an equivalent efficiency of lowering intraocular pressure with AZOPT® (1% BRZ) in vivo. These results identified the BRZ-HP-β-CD inclusion complex might have a promising future as a novel formulation of BRZ for glaucoma treatment. 相似文献
9.
The objective of this study was to improve the water-solubility and photostability of cilnidipine by complexing it with hydroxypropyl-β-cyclodextrin (HP-β-CD or HP-beta-CD). The interactions of cilnidipine and HP-β-CD were characterized by ultra violet-visible (UV/VIS) spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transformation-infrared (FT-IR) spectroscopy and (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy to verify the formation of cilnidipine-HP-β-CD complex inclusion. Moreover, the binding sites in the HP-β-CD structure were also tracked through (1)H NMR spectroscopy analysis. All the characterization information proved the formation of cilnidipine-HP-β-CD inclusion complex, and the results demonstrated the superiority of the inclusion complex in dissolution rates and photostability; in addition, the apparent solubility of cilnidipine was increased more than 10,000-fold in the presence of HP-β-CD. The stability constant (1:1) was found to be 50,116M(-1), suggesting a high tendency of the drug to enter the HP-β-CD cavity. These results identified the cilnidipine-HP-β-CD inclusion complex as an effective new approach to design a novel formulation for pharmaceutical application. 相似文献
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The more potent inhibitory activity against angiotensin-converting enzyme (ACE) was excised from a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) preparation of Bacillus stearothermophilus by heating at 120°C in 1 m AcOH–20mm HCI, as compared with GAPDH preparations of yeast and pig. Sufficient excision of B. stearothermophilus ACE inhibitors required a longer proteolysis time of 60 min. Two inhibitors were then purified by gel-permeation and reverse-phase chromatog-raphies. One of the B. stearothermophilus ACE inhibitors, BG-1, was the GAPDH peptide 68–77 (Gly-Lys-Glu-Ile-Ile-Val-Lys-Ala-Glu-Arg, IC50: 32 μm). Another inhibitor, BG-2 (Gly-Lys-Met-Val-Lys-Val-Val-Ser-Trp-Tyr, IC50: 6 μM), corresponded to GAPDH peptide 304–313. These sequences were quite different from those of vertebrate GAPDH peptides and the venom peptide family with ACE inhibitory activity. BG-2 was found to be a non-competitive type inhibitor, differing from many natural peptide inhibitors. Thus, B. stearothermophilus GAPDH seemed to be a good source of new type ACE inhibitors, in addition to the advantages due to its thermophilic property. 相似文献
12.
Hidehiko Tanaka Hirotsugu Imahara Nobuyoshi Esaki Kenji Soda 《Bioscience, biotechnology, and biochemistry》2013,77(4):1021-1022
A chemically defined medium was devised to examine the growth, production and biochemical pathway of tetrocarcin A. The production of tetrocarcin A was greatly stimulated by l-feucine and its corresponding keto acid, α-ketoisocaproate, suggesting that l-leucine is involved in the biosynthesis of tetrocarcin A. About 10–12 μg/ml of tetrocarcin A was produced in a chemically defined medium consisting of 20 g sucrose, 2.5 g KNO3, 5 g MgSO4·7H2O, 5 g KH2PO4 and 1 g l-leucine per liter of water (pH 7.0). 相似文献
13.
Mátrai J Jonckheer A Joris E Krüger P Carpenter E Tuszynski J De Maeyer M Engelborghs Y 《European biophysics journal : EBJ》2008,38(1):13-23
Correlating the experimentally observed kinetics of protein conformational changes with theoretical predictions is a formidable
and challenging task, due to the multitude of degrees of freedom (>5,000) in a protein and the huge gap between the timescale
of the kinetic event of interest (ms) and the typical timescale of computer simulations (ns). In this study we show that using
the targeted molecular dynamics (TMD) method it is possible to simulate conformational changes of the ms time range and to
correlate multiple simulations of single pathways with ensemble experiments on both the structural and energetic basis. As
a model system we chose to study the conformational change of rat-Δα-chymotrypsin from its inactive to its active conformation.
This activation process has been analyzed previously by experimental and theoretical methods, i.e. fluorescence stopped-flow
spectroscopy (FSF), molecular dynamics (MD) and TMD. Inspired by the results of these studies on the wild type (WT) enzyme,
several mutants were constructed to alter the conformational pathway and studied by FSF measurements. In the present work
WT and mutant N18G were subjected to multiple MD and subsequent TMD simulations. We report the existence of two main activation
pathways, a feature of chymotrypsin activation that has been hitherto unknown. A method to correlate the energetics of the
different pathways calculated by TMD and the kinetic parameters observed by experimental methods such as FSF is presented.
Our work is relevant for experimental single molecule studies of enzymes in general.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
R. O. Gillhespy 《BMJ (Clinical research ed.)》1959,1(5121):556-557
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Sharova NP Abramova EB Dmitrieva SB Dimitrova DD Mikhailov VS 《Biochemistry. Biokhimii?a》2001,66(4):402-409
The interaction of DNA polymerase purified from eggs of the teleost fish Misgurnus fossilis (loach) with DNA duplexes with single-strand gaps of 1-13 nucleotides was studied. In the absence of template-restricting DNA, the enzyme elongated primers on single-stranded DNA templates in a distributive manner. However, in the presence of the proximal 5"-terminus restricting the template, the enzyme activity significantly increased. In this case, the enzyme was capable of processive synthesis by filling gaps of 5-9 nucleotides in DNA duplexes. These data indicate that DNA polymerase can interact with both the 3"- and 5"-termini located upstream and downstream from the gap. Analysis of the complexes formed by DNA polymerase and different DNA substrates by electrophoretic mobility shift assay confirmed the assumption that this enzyme can interact with the proximal 5"-terminus restricting the gap. DNA polymerase displayed much higher affinity in duplexes with gaps of approximately 10 nucleotides compared to the standard template–primer complexes. Maximal affinity was observed in experiments with DNA substrates containing unpaired 3"-tails in primers. The results of this study suggest that DNA polymerase exerts high activity in the cell nuclei during repair of DNA intermediates with single strand gaps and unpaired 3"-termini. 相似文献
16.
Eugenia Soru 《Molecular and cellular biochemistry》1979,23(3):185-192
Summary Obvious protection of the catalytic activity of Esch. coli L-asparaginase by 2-macroglobulin (2M) was observed under conditions otherwise propitious to the dissociation of the tetrameric molecule into inactive subunits, i.e. very diluted enzyme solutions or the presence of either SDS or urea. The degree of protection depended on enzyme and 2M concentrations respectively, and on the preincubation time of the 2M-enzyme mixture prior to substrate addition. The formation of a catalytically active complex between 2M and L-asparaginase was confirmed by gel filtration on a Sephadex-G column and by polyacrylamide gel electrophoresis. The fact that the migration distance of the active complex corresponded to the migration of 2M and the absence in that case of a migration band corresponding to the intact molecule suggest that complexing of the enzyme with 2M prevented its dissociation into subunits and thus its inactivation. Addition of 2M to the already dissociated enzyme molecule did not restore its catalytic activity.Alpha2-macroglobulin was shown to have an inhibiting effect on the proteolytic activity of almost all proteases and no effect on their esterolytic activity. Furthermore, it prevents the inhibition of esterolytic activity by some natural compounds1–5. The effect of 2M on other types of catalytic activity has not been investigated enough to afford a generalization of the possible role of this macroglobulin in the control of enzyme activity in the body.This paper reports the results of an in vitro study of the effect of 2M on the catalytic activity of an important amidase, i.e. L-asparaginase (L-asparagine amidohydrolase 3.5.1.1), which in recent years has been used in the treatment of acute lymphocytic leukemia in children6,7.Abbreviations 2M
2-macroglobulin
- E
enzyme
- SDS
sodium dodecylsulfate
Part of the results were reported at the 10th International Congress of Biochemistry, Hamburg 1976, Abst. p. 377. 相似文献
17.
Maier Gerhard; Berger Irmgard; Burghard Wiebke; Nassal Brigitte 《Journal of plankton research》2000,22(10):1977-1987
In laboratory experiments, we tested whether the cyclopoid copepodCyclops vicinus is more vulnerable to predation by juvenile(young-of-the-year) roach (Rutilus rutilus) and/or larvae ofthe phantom midge Chaoborus flavicans during mating than individualadult copepods of the same species. We also tested whether C.vicinusavoided mating, displayed shorter mating times and/or loweractivity when a predator (Chaoborus) was present, or when exposedto water in which predators (Chaoborus) were previously held.Fish ate the same quantity of pairs in copulation and individualegg-bearing females but significantly fewer females withouteggs. Chaoborus ate similar quantities of pairs and femalesbut fewer males. Pairs in copulation and egg-bearing femaleswere detected earlier by fish than individual non-ovigerousfemales or males, and pairs in copulation were captured mosteasily by fish. Cyclops vicinus mated less often when Chaoboruslarvae were present than in water in which Chaoborus was previouslyheld, or in pure tap water. However, predator presence or exposureto predator-treated water had no effect on (i.e. did not reduce)mating duration. Activity of C.vicinus pairs during copulationwas significantly lower when a predator was present, or in predator-treatedwater, than in pure tap water, and activity of pairs decreasedwith increasing activity of the predator. Although our experimentswere carried out under artificial conditions which cannot betransferred to the complex conditions in the field, they suggestthat mating in copepods is dangerous and that copepods haveevolved particular strategies to reduce the risk of predationduring mating. 相似文献
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Starch gel electrophoretic and ultracentrifuge methods failed to demonstrate any differences between the hemoglobins of mice of the Shanghai and HBBP/Cag strains and crosses among these strains. The apparent identity of these hemoglobins is thought to stem from the contribution of Asian mice to the British mouse fancy from which the laboratory strains having Hbb-p in part descerd. Maleate buffer of pH 7 or above can be used to prevent the formation of disulfide-bridged dimers of mouse hemoglobins. However, the minor electrophoretic bands of Hbb-p and Hbb-d react with approximately twice as much maleate as the major bands of each of these hemoglobins, although the minor bands like the major contain only one free cysteine group per chain. This can be explained by the alkylation of the -amino of lysine residue 76, but some evidence for the alkylation of histidine in the minor band of Hbb-p is also presented. 相似文献
19.
Absorption and luminescence excitation and emission spectra of newly synthesized 2-(4-methylphenylimino)-3-(2 -benzothiazolyl)benz-alpha-chromene (BCBT) have been studied in the presence of various DNA concentrations. BCBT is characterized by the existence of two different fluorescent systems, exhibiting radiationless fluorescence resonance energy transfer between them. In the range of molar ratios of polynucleotide/dye concentrations from 0 to 50, BCBT preferentially intercalates into DNA due to its benz-alpha-chromene fragment, whereas the 2-benzothiazolyl fragment is responsible for fluorescence. 相似文献
20.
Pore formation in lipid bilayers by channel-forming peptides and toxins is thought to follow voltage-dependent insertion of amphipathic α-helices into lipid bilayers. We have developed an approximate potential for use within the CHARMm molecular mechanics program which enables one to simulate voltage-dependent interaction of such helices with a lipid bilayer. Two classes of helical peptides which interact with lipid bilayers have been studied: (a) δ-toxin, a 26 residue channel-forming peptide from Staphylococcus aureus; and (b) synthetic peptides corresponding to the α5 and α7 helices of the pore-forming domain of Bacillus thuringiensis CryIIIA δ-endotoxin. Analysis of δ-toxin molecular dynamics (MD) simulations suggested that the presence of a transbilayer voltage stabilized the inserted location of δ-toxin helices, but did not cause insertion per se. A series of simulations for the α5 and α7 peptides revealed dynamic switching of the α5 helix between a membrane-associated and a membrane-inserted state in response to a transbilayer voltage. In contrast the α7 helix did not exhibit such switching but instead retained a membrane associated state. These results are in agreement with recent experimental studies of the interactions of synthetic α5 and α7 peptides with lipid bilayers. 相似文献