Membrane biochemistry最新文献_第9页

Dietary modifications of phospholipid composition and biophysical properties of the brush border membrane along the trout intestine. 饲料对鳟鱼肠刷状缘膜磷脂组成及生物物理特性的影响。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709029429

X Pelletier, G Duportail, C Leray

引用次数: 8

Modification by S-adenosyl-L-homocysteine of norepinephrine in-vitro uptake in rat brain homogenates. s -腺苷- l-同型半胱氨酸对大鼠脑匀浆中去甲肾上腺素体外摄取的影响。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709039989

P Fonlupt, C Rey, H Pacheco

引用次数: 1

Cardiac sarcolemmal substrate of the cGMP-dependent protein kinase. cgmp依赖性蛋白激酶的心肌上皮底物。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709039990

J Cuppoletti, J Thakkar, N Sperelakis, G Wahler

引用次数: 18

High affinity stereospecific binding of [3H] cocaine in striatum and its relationship to the dopamine transporter. [3H]可卡因在纹状体中的高亲和力立体特异性结合及其与多巴胺转运体的关系。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709039986

D O Calligaro, M E Eldefrawi

{"title":"High affinity stereospecific binding of [3H] cocaine in striatum and its relationship to the dopamine transporter.","authors":"D O Calligaro, M E Eldefrawi","doi":"10.3109/09687688709039986","DOIUrl":"https://doi.org/10.3109/09687688709039986","url":null,"abstract":"A high affinity (KD 35 nM) binding site for [3H]cocaine is detected in rat brain striatum present at 2-3 pmol/mg protein of synaptic membranes. This binding is displaced by cocaine analogues with the same rank order as their inhibition of [3H]dopamine ([3H]DA) uptake into striatal synaptosomes (r = 0.99), paralleling the order of their central stimulant activity. The potent DA uptake inhibitors nomifensine, mazindol, and benztropine are more potent inhibitors of this high affinity [3H]cocaine binding than desipramine and imipramine. Cathinone and amphetamine, which are more potent central stimulants than cocaine, displace the high affinity [3H]cocaine binding stereospecifically, but with lower potency (IC50 approximately equal to 1 microM) than does cocaine. It is suggested that the DA transporter in striatum is the putative \"cocaine receptor.\" Binding of [3H]cocaine, measured in 10 mM Na2HPO4-0.32 M sucrose, pH 7.4 buffer, is inhibited by physiologic concentrations of Na+ and K+ and by biogenic amines. DA and Na+ reduce the affinity of the putative \"cocaine receptor\" for [3H]cocaine without changing the Bmax, suggesting that inhibition may be competitive. However, TRIS reduces [3H]cocaine binding noncompetitively while Na+ potentiates it in TRIS buffer. Binding of [3H]mazindol is inhibited competitively by cocaine. In phosphate-sucrose buffer, cocaine and mazindol are equally potent in inhibiting [3H]mazindol binding, but in TRIS-NaCl buffer cocaine has 10 times lower potency. It is suggested that the cocaine receptor in the striatum may be an allosteric protein with mazindol and cocaine binding to overlapping sites, while Na+ and DA are allosteric modulators, which stabilize a lower affinity state for cocaine.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"7 2","pages":"87-106"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687688709039986","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14578542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 123

Regulation of cardiac sarcoplasmic reticulum function by phospholamban. 磷蛋白对心肌肌浆网功能的调节。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709039993

I Edes, E G Kranias

{"title":"Regulation of cardiac sarcoplasmic reticulum function by phospholamban.","authors":"I Edes, E G Kranias","doi":"10.3109/09687688709039993","DOIUrl":"https://doi.org/10.3109/09687688709039993","url":null,"abstract":"Calcium fluxes across the sarcoplasmic reticulum membrane are regulated by phosphorylation of a 27,000-dalton membrane-bound protein termed phospholamban. Phospholamban is phosphorylated by three different protein kinases (cAMP-dependent, Ca2+.CAM-dependent and Ca2+.phospholipid dependent) at apparently distinct sites. Phosphorylation by each of the protein kinases increases the rates of active calcium transport by sarcoplasmic reticulum vesicles. The stimulatory effects of protein kinases on the calcium pump may be reversed by an endogenous protein phosphatase activity. The phosphoprotein phosphatase can dephosphorylate both the cAMP-dependent and the Ca2+.CAM-dependent sites of phospholamban. Phosphorylation of phospholamban also occurs in situ, in perfused beating hearts, during the peak of the inotropic response to beta-adrenergic stimulation. Reversal of the stimulatory effects is associated with dephosphorylation of phospholamban. Thus, in vivo and in vitro studies suggest that phospholamban is a regulator for the calcium pump in cardiac sarcoplasmic reticulum. The degree of phospholamban phosphorylation determined by the interaction of specific protein kinases and phosphatases may represent an important control for sarcoplasmic reticulum function and, thus, for the contraction-relaxation cycle in the myocardium. In this review, we summarize recent evidence on physical and structural properties of phospholamban, the proposed structural molecular models for this protein, and the significance of its regulatory role both in vitro and in situ.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"7 3","pages":"175-92"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687688709039993","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13992087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 26

Modulation of lysine transport in cultured rat astrocytes and astrocytoma cells. 大鼠星形胶质细胞和星形细胞瘤细胞中赖氨酸转运的调节。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709029435

L C Mokrasch

引用次数: 2

Effect of SH-group reagents on net water transport in frog urinary bladder. sh -基团试剂对青蛙膀胱净水分输送的影响。

Membrane biochemistry Pub Date : 1987-01-01 DOI: 10.3109/09687688709029427

N Adragna, J Bourguet

{"title":"Effect of SH-group reagents on net water transport in frog urinary bladder.","authors":"N Adragna, J Bourguet","doi":"10.3109/09687688709029427","DOIUrl":"https://doi.org/10.3109/09687688709029427","url":null,"abstract":"The basal rate of water reabsorption and its acceleration by oxytocin, cyclic AMP (cAMP) or serosal hypertonicity in frog urinary bladders were monitored before and after exposure of the mucosal surface to sulfhydryl (SH) reactive reagents. The following observations were made: 1. N-ethylmaleimide (NEM, 10(-5)M) did not modify the basal water flux, but did potentiate the hydrosmotic response to oxytocin. At higher NEM concentrations, an increase in the basal flux was observed, while the oxytocin-induced water flux was strongly inhibited, if not, nullified. 2. Iodoacetamide (IAM, 10(-3)M) did not modify the basal water flux but did inhibit the oxytocin-, cAMP-, and serosal hypertonicity-induced increase in water permeability. Furthermore, the time course of the hydrosmotic response to oxytocin was significantly increased. 3. 5,5' dithio-bis-(2-nitrobenzoic acid) (DTNB, 10(-3)M) modified neither the basal nor the oxytocin-induced water flux when incubated at pH 8.1, but potentiated the inhibitory effect of NEM. However, at a mucosal pH of 6.5, DTNB inhibited the response to oxytocin by 30%. These results suggest that: (1) the three SH reagents affect differently the basal and the oxytocin-induced water pathways; and that (2) each of the changes in the oxytocin-induced paths occurs at a step following the hormonally-induced increase in intracellular cAMP concentration.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"7 1","pages":"23-39"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687688709029427","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14625285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Quenching of red cell tryptophan fluorescence by mercurial compounds. 汞化合物对红细胞色氨酸荧光的猝灭作用。

Membrane biochemistry Pub Date : 1986-01-01 DOI: 10.3109/09687688609065453

A S Verkman, M F Lukacovic, M S Tinklepaugh, J A Dix

{"title":"Quenching of red cell tryptophan fluorescence by mercurial compounds.","authors":"A S Verkman, M F Lukacovic, M S Tinklepaugh, J A Dix","doi":"10.3109/09687688609065453","DOIUrl":"https://doi.org/10.3109/09687688609065453","url":null,"abstract":"Intrinsic tryptophan fluorescence in red cell ghost membranes labeled with N-ethylmaleimide (N-EM) is quenched in a dose-dependent manner by the organic mercurial p-chloromercuribenzene sulfonate (p-CMBS). Fluorescence lifetime analysis shows that quenching occurs by a static mechanism. Binding of p-CMBS occurs by a rapid (less than 5 s) biomolecular association (dissociation constant K1 = 1.8 mM) followed by a slower unimolecular transition with forward rate constant k2 = 0.015 s-1 and reverse rate constant k-2 = 0.0054 s-1. Analysis of the temperature dependence of k2 gives delta H = 6.5 kcal/mol and delta S = -21 eu. The mercurial compounds p-chloromercuribenzoic acid, p-aminophenylmercuric acetate, and mercuric chloride quench red cell tryptophan fluorescence by the same mechanism as p-CMBS does; the measured k2 value was the same for each compound, whereas K1 varied. p-CMBS also quenches the tryptophan fluorescence in vesicles reconstituted with purified band 3, the red cell anion exchange protein, in a manner similar to that in ghost membranes. These experiments define a mercurial binding site on band 3 in ghosts treated with N-EM and establish the binding mechanism to this site. The characteristics of this p-CMBS binding site on band 3 differ significantly from those of the p-CMBS binding site involved in red cell water and urea transport inhibition.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"6 4","pages":"269-89"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687688609065453","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14696634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Phospholamban involvement in the maintenance of basal calcium transport in cardiac sarcoplasmic reticulum. 磷蛋白参与心脏肌浆网基础钙转运的维持。

Membrane biochemistry Pub Date : 1986-01-01 DOI: 10.3109/09687688609065456

I S Ambudkar, D T Fanfarillo, A E Shamoo

引用次数: 3

Apocytochrome c induces pH-dependent vesicle fusion. 细胞色素c诱导ph依赖性囊泡融合。

Membrane biochemistry Pub Date : 1986-01-01 DOI: 10.3109/09687688609065450

A Walter, D Margolis, R Mohan, R Blumenthal

{"title":"Apocytochrome c induces pH-dependent vesicle fusion.","authors":"A Walter, D Margolis, R Mohan, R Blumenthal","doi":"10.3109/09687688609065450","DOIUrl":"https://doi.org/10.3109/09687688609065450","url":null,"abstract":"The ability of apocytochrome c and the heme containing respiratory chain component, cytochrome c, to induce fusion of phosphatidylcholine (PC) small unilamellar vesicles containing 0-50 mol % negatively charged lipids was examined. Both molecules mediated fusion of phosphatidylserine (PS):PC 1:1 vesicles as measured by energy transfer changes between fluorescent lipid probes in a concentration- and pH-dependent manner, although cytochrome c was less potent and interacted over a more limited pH range than the apocytochrome c. Maximal fusion occurred at pH 3, far below the pKa of the 19 lysine groups contained in the protein (pI = 10.5). A similar pH dependence was observed for vesicles containing 50 mol % cardiolipin (CL), phosphatidylglycerol (PG), and phosphatidylinositol (PI) in PC but the apparent pKa values varied somewhat. In the absence of vesicles, the secondary structure of apocytochrome c was unchanged over this pH range, but in the presence of negatively charged vesicles, the polypeptide underwent a marked conformational change from random coil to alpha-helix. By comparing the pH dependencies of fusion induced by poly-L-lysine and apocytochrome c, we concluded that the pH dependence derived from changes in the net charge on both the vesicles and apocytochrome c. Aggregation could occur under conditions where fusion was imperceptible. Fusion increased with increasing mole ratio of PS. Apocytochrome c did induce some fusion of vesicles composed only of PC with a maximum effect at pH 4. Biosynthesis of cytochrome c involves translocation of apocytochrome c from the cytosol across the outer mitochondrial membrane to the outer mitochondrial space where the heme group is attached. The ability of apocytochrome c to induce fusion of both PS-containing and PC-only vesicles may reflect characteristics of protein/membrane interaction that pertain to its biological translocation.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"6 3","pages":"217-37"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687688609065450","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14162335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27