酪氨酸蛋白激酶抑制剂Tyrphostin AG114对重组人蛋白激酶CK2全酶的抑制作用(英文)

目的　为了观察TyrphostinAG114对重组人蛋白激酶CK2全酶的直接作用及其酶动力学机理。方法　利用基因工程克隆 ,表达和纯化获得重组人蛋白激酶CK2α和 β亚基 ,在体外等摩尔数混合构成有最大生物活性的重组CK2全酶 ,在不同条件下测定CK2的活性。CK2活性通过测定转移到CK2底物上的 [γ 32 P]ATP或 [γ 32 P]GTP的 [32 P]放射活度来检测。结果　重组人CK2是一种Ca2 +、cAMP和cGMP等第二信使非依赖性蛋白激酶 ,与天然CK2的性质一致。AG114对重组人CK2全酶具有很强的抑制作用 ,IC50 为 2 0 .8μmol·L- 1,抑制强度介于已知CK2抑制剂 5 ,6 二氯 1 β 呋喃糖苯并咪唑 (DRB)和N (2 氨乙基 ) 5 氯萘 1 硫胺 (A3)之间。AG114对重组人CK2的动力学研究表明 :它与GTP呈混合竞争性抑制作用 ,与酪蛋白呈非竞争性抑制作用。结论　AG114不仅是酪氨酸蛋白激酶的抑制剂 ,而且是一种十分有效的蛋白激酶CK2的抑制剂。重组人蛋白激酶CK2可作为一种较为简便地筛选和开发有效的CK2抑制剂的分子靶点     

AG1112对重组人蛋白激酶CK2全酶的抑制作用

目的　观察Tyrphostin中的AG1112对重组人蛋白激酶CK2全酶的直接作用及其酶动力学机制。方法　利用基因工程克隆、表达和纯化获得重组人蛋白激酶CK2α和 β亚基 ,在体外等摩尔数混合构成有最大生物活性的重组CK2全酶 ,在不同条件下测定CK2的活性。CK2活性通过测定转移到CK2底物上的 [γ 3 2 P]ATP或 [γ 3 2 P]GTP的 [3 2 P]放射活度来检测。结果　重组人CK2是一种Ca2 + 、cAMP和cGMP等第二信使非依赖性蛋白激酶 ,与天然CK2的性质一致。AG1112对重组人CK2全酶具有很强的抑制作用 ,IC50 为 6 0 μmol·L-1,抑制作用大于CK2已知抑制剂DRB和A3。AG1112对重组人CK2的动力学研究表明 :它与GTP和酪蛋白分别呈混合性和非竞争性抑制作用。结论　由于AG1112对重组人CK2显示出很强的抑制作用 ,因此重组人蛋白激酶CK2可作为一种较为简便筛选和开发有效的CK2抑制剂的分子靶点     

Tyrphostin AG1478对重组人蛋白激酶CK2全酶的抑制作用及其动力学分析

目的:观察Tyrphostin AG1478[4-(3-氯苯胺基)-6,7-二甲氧喹唑啉]对重组人蛋白激酶CK2全酶的直接作用及其酶动力学机制.方法:在体外等摩尔数混合重组蛋白激酶CK2α和β亚基构成CK2全酶,在不同条件下测定CK2的活性.CK2活性通过测定转移到CK2底物上的[γ-~(32)P]ATP或[γ-~(32)P]GTP的~(32)P放射活度来检测.结果:重组人CK2是一种Ca~(2 )、[KG*2]cAMP和cGMP等第二信使非依赖性蛋白激酶,与天然CK2的性质一致.AG1478对重组人CK2全酶具有很强的抑制作用,IC_(50)为25.9μmol/L,抑制作用接近于已知的CK2抑制剂N-(2-氨乙基)-5-氯萘-1-硫胺(A3),稍小于5,6-二氯-1-β-呋喃糖苯并咪唑(DRB).AG1478对重组人CK2的动力学研究表明:它与GTP和酪蛋白均呈竞争性抑制作用,是一种双底物抑制剂.结论:AG1478不仅是高效特异的表皮生长因子受体酪氨酸蛋白激酶的抑制剂,而且也是一种新型有效的蛋白激酶CK2抑制剂.重组人蛋白激酶CK2可作为一种较为简便的筛选和开发有效CK2抑制剂的分子靶点.     

Tyrphostin AG34对重组人蛋白激酶CK2全酶的影响

目的:观察TyrphostinAG34对重组人蛋白激酶CK2全酶的直接作用及其酶动力学机制。方法:利用基因工程克隆、表达和纯化获得重组人蛋白激酶CK2α和β亚基,在体外等摩尔数混合构成有最大生物活性的重组CK2全酶,在不同条件下测定CK2的活性。CK2活性通过测定转移到CK2底物上的[γ-³²P]ATP或[γ-³²P]GTP的[³²P]放射活度来检测。结果:重组人CK2是一种Ca²⁺、cAMP和cGMP等第二信使非依赖性蛋白激酶,与天然CK2的性质一致。AG34对重组人CK2全酶具有很强的抑制作用,IC₅₀为1.0 μmol·L^-1,抑制作用远大于CK2已知抑制剂5 ,6 -二氯-1-β-呋喃糖苯并咪唑(DRB)和N-(2-氨乙基)-5-氯萘-1-硫胺(A3)。AG34对重组人CK2的动力学研究表明:它与GTP呈现以竞争性为主的混合型抑制作用,与酪蛋白呈非竞争性抑制作用。结论:AG34不仅是酪氨酸蛋白激酶的抑制剂,而且是一种十分有效的蛋白激酶CK2的抑制剂.重组人蛋白激酶CK2可作为一种较为简便筛选和开发有效的CK2抑制剂的分子靶点。     

AG1112对重组人蛋白激酶CK2全酶的抑制作用

目的观察Tyrphostin中的AG1112对重组人蛋白激酶CK2全酶的直接作用及其酶动力学机制.方法利用基因工程克隆、表达和纯化获得重组人蛋白激酶CK2α和β亚基,在体外等摩尔数混合构成有最大生物活性的重组CK2全酶,在不同条件下测定CK2的活性.CK2活性通过测定转移到CK2底物上的[γ-32P]ATP或[γ-32P]GTP的 [32P]放射活度来检测.结果重组人CK2是一种Ca2+、c AMP和cGMP等第二信使非依赖性蛋白激酶,与天然CK2的性质一致.AG1112对重组人CK2全酶具有很强的抑制作用,IC50为6.0 μmol·     

氨氯吡咪对重组人蛋白激酶CK2全酶的抑制动力学

目的　了解氨氯吡咪对重组人蛋白激酶CK2全酶的直接作用及其酶动力学机制。方法　利用基因工程克隆、表达和纯化获得重组人蛋白激酶CK2α和 β亚基 ,在体外等摩尔数混合构成有最大生物活性的重组CK2全酶 ,在不同条件下通过测定转移到CK2底物上的 [γ 3 2 P]GTP的 [3 2 P]放射活度来测定CK2的活性。结果　氨氯吡咪对重组人CK2全酶具有抑制作用 ,IC50 为 2 5 7 5 7μmol·L-1 。氨氯吡咪对重组人CK2全酶的动力学研究表明 :它与GTP呈竞争性抑制作用 ,抑制常数Ki 值为 2 36 30 μmol·L-1 ;与酪蛋白呈非竞争性抑制作用 ,抑制常数Ki 值为 1 6 3 6 3μmol·L-1 。结论　氨氯吡咪除了能抑制cAMP或ATP依赖的酶以外 ,还可以抑制以GTP为磷酸供体的蛋白激酶。重组人蛋白激酶CK2可作为一种较为简便筛选和开发有效的CK2抑制剂的分子靶点     

槲皮素-7-硫酸酯钠盐对重组人蛋白激酶CK2全酶的影响

目的　观察槲皮素 7 硫酸酯钠盐 (SQMS)对重组人CK2全酶的直接作用及酶动力学机制。方法　通过测定转移到CK2底物上的 [γ 3 2 P]ATP的 [3 2 P]放射活度检测不同条件下的重组人CK2全酶的活性。结果　SQMS对重组人CK2全酶有很强的抑制作用 ,IC50 为 1 37μmol·L-1。CK2的动力学研究表明 :SQMS与ATP和酪蛋白分别呈竞争性和非竞争性抑制作用。结论　SQMS是CK2的抑制剂 ,SQMS的抑制作用与ATP呈竞争性、与酪蛋白呈非竞争性     

槲皮素-7,4′-二硫酸酯钠对重组人CK2全酶的抑制作用及动力学分析

目的　观察槲皮素 7,4′ 二硫酸酯钠 (sodiumquercetin 7,4′ disulphate ,SQDS)对重组人CK2全酶的直接作用及酶动力学机制。方法　通过测定转移到CK2底物上的 [γ 3 2 P]ATP的3 2 P放射活度检测不同条件下的重组人CK2全酶的活性。结果　重组人CK2是一种Ca2 +,cAMP和cGMP等第二信使非依赖性蛋白激酶 ,与天然CK2的性质一致。SQDS对重组人CK2全酶有很强的抑制作用 ,IC50 为 4 4μmol·L- 1 ,抑制作用大于已知CK2抑制剂DRB和A3。CK2的动力学研究表明 :SQDS与ATP和酪蛋白分别呈竞争性和非竞争性抑制作用。结论　SQDS是有效的CK2抑制剂 ,对于开发更有效的CK2抑制剂及将SQDS用于临床提供了一定的实验依据。     

木犀草素对蛋白激酶CK2的抑制作用

目的观察体外以及细胞内木犀草素对蛋白激酶CK2活性的抑制效果及进行酶动力学分析以确定其抑制作用类型。方法将利用基因工程技术获得的重组人CK2α′及β亚基在体外等摩尔混合构成CK2全酶。通过测定药物作用后转移到CK2底物上的[γ3-2P]ATP的32P的放射性活度,探讨木犀草素对重组人CK2全酶以及HL-60细胞内CK2活性的抑制作用,并采用L ineweaver-Burk作图法分析其酶动力学机制。结果木犀草素能显著抑制重组人CK2活性(IC50=0.86μmol.L-1)以及HL-60细胞内的CK2活性,其对细胞内CK2的作用效果要强于阳性对照TBB。酶动力学分析表明,木犀草素与ATP呈竞争性抑制CK2的活性(Ki=0.19μmol.L-1),与酪蛋白则呈混合性抑制CK2的活性(Ki=0.11μmol.L-1)。结论木犀草素是一种有效的蛋白激酶CK2的抑制剂。     

槲皮素-7,4′-二硫酸酯钠对重组人CK2全酶的抑制作用及动力学分析

目的观察槲皮素-7,4′-二硫酸酯钠(sodium quercetin-7,4′-disulphate,SQDS)对重组人CK2全酶的直接作用及酶动力学机制。方法通过测定转移到CK2底物上的［γ-³²P］ATP的³²P放射活度检测不同条件下的重组人CK2全酶的活性。结果重组人CK2是一种Ca²⁺,cAMP和cGMP等第二信使非依赖性蛋白激酶,与天然CK2的性质一致。SQDS对重组人CK2全酶有很强的抑制作用,IC₅₀为4.4 μmol·L^-1,抑制作用大于已知CK2抑制剂DRB和A3。CK2的动力学研究表明:SQDS与ATP和酪蛋白分别呈竞争性和非竞争性抑制作用。结论SQDS是有效的CK2抑制剂,对于开发更有效的CK2抑制剂及将SQDS用于临床提供了一定的实验依据。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.