Membrane biochemistry最新文献_第2页

Solubilization of multilamellar liposomes in the presence of non-ionized drug. 非电离药物存在下多层脂质体的增溶作用。

Membrane biochemistry Pub Date : 1993-07-01 DOI: 10.3109/09687689309150261

M J Habib, C O Akogyeram, E N Ngofa, M Biswas, G V Betageri

{"title":"Solubilization of multilamellar liposomes in the presence of non-ionized drug.","authors":"M J Habib, C O Akogyeram, E N Ngofa, M Biswas, G V Betageri","doi":"10.3109/09687689309150261","DOIUrl":"https://doi.org/10.3109/09687689309150261","url":null,"abstract":"The solubilization of multilamellar liposomes by metoprolol tartrate (MPL) has been studied as a function of pH, [MPL], [dimyristoylphosphatidylcholine (DMPC)], temperature and lipid composition. The solubilization of liposomes at 37 degrees C by 7.3 nM MPL occurred at different rates at different pH values. MPL completely solubilized by 7.2 mM DMPC liposomes after about 17 h at pH 12, but only a partial solubilization occurred at pH 10 and 11. Between pH 7 and 9 no change in turbidity was observed after 1 week. Addition of cholesterol (CHOL) to DMPC (2:1 mol) had very little effect on solubilization after 24 h, however with DMPC:CHOL (5:1 mol) the decrease in turbidity was observed after 24 h, even though solubilization was much less compared with that of DMPC alone. The rate of solubilization was decreased when dipalmitoylphosphatidylcholine liposomes were employed. Addition of dicetylphosphate (DCP) to DMPC liposomes reduced the rate of solubilization significantly. The solubilization of liposomes by 7.3 mM MPL as a function of [DMPC], indicated that the lower the liposome concentration the greater the effect on solubilization. It is concluded that MPL in the non-ionized form has a solubilizing effect on liposomes, and addition of CHOL or DCP to DMPC has a stabilizing effect against solubilization.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 3","pages":"145-54"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150261","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19221497","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: 0

Duramycin increases intracellular calcium in airway epithelium. 杜拉霉素增加气道上皮细胞内钙。

Membrane biochemistry Pub Date : 1993-04-01 DOI: 10.3109/09687689309150258

M M Cloutier, L Guernsey, R I Sha'afi

{"title":"Duramycin increases intracellular calcium in airway epithelium.","authors":"M M Cloutier, L Guernsey, R I Sha'afi","doi":"10.3109/09687689309150258","DOIUrl":"https://doi.org/10.3109/09687689309150258","url":null,"abstract":"Duramycin increases short-circuit current (Isc) and net Cl- secretion in tracheal epithelium. We measured the intracellular free calcium ([Ca2+]i) response to duramycin using Indo-1 and bovine and canine tracheal cell suspensions, and the effect of an intracellular calcium chelator, BAPTA, and the protein kinase C inhibitor, staurosporine, on the Isc and [Ca2+]i response to duramycin. [Ca2+]i increased in a dose-dependent manner from basal levels of 34 +/- 5 to 949 +/- 136 nM at 5 x 10(-6) M duramycin. Both BAPTA (50 microM) and staurosporine (5-50 nM) pretreatment blunted the increase in Isc and net Cl- secretion produced by duramycin. BAPTA also blunted the rise in [Ca2+]i produced by duramycin (5 x 10(-6) M) in the presence of extracellular calcium (499 +/- 122 nM). In the absence of extracellular calcium, the duramycin-induced (5 x 10(-6) M) rise in [Ca2+]i was blunted from 949 +/- 136 nM (stimulation in the presence of Ca2+) to 621 +/- 122 nM, and was further decreased in the presence of BAPTA to 197 +/- 42 nM. In contrast, staurosporine (50 nM) pretreatment had no effect on the rise in [Ca2+]i produced by duramycin (basal 90 +/- 27 to 861 +/- 110 nM at 5 x 10(-6) M). Duramycin had no effect on [Ca2+]i in human neutrophils. These data demonstrate that duramycin releases calcium from intracellular stores and stimulates the influx of calcium in airway epithelial cells. These data also demonstrate that, in the presence of protein kinase C pathway blockade, an increase in intracellular free calcium is not sufficient for chloride secretion; thus, duramycin-stimulated chloride secretion may depend upon protein kinase C.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 2","pages":"107-18"},"PeriodicalIF":0.0,"publicationDate":"1993-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150258","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19348121","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: 34

Volume-dependent potassium transport in camel red blood cells. 骆驼红细胞中钾的体积依赖性运输。

Membrane biochemistry Pub Date : 1993-04-01 DOI: 10.3109/09687689309150257

N S Gharaibeh, N M Rawashdeh

引用次数: 2

Lipopolysaccharide in combination with serum potentiates the stimulated activity of phospholipase D in human neutrophils via CD14. 脂多糖与血清结合可通过CD14增强人中性粒细胞中受刺激的磷脂酶D活性。

Membrane biochemistry Pub Date : 1993-04-01 DOI: 10.3109/09687689309150255

K Yasui, E L Becker, R I Sha'afi

{"title":"Lipopolysaccharide in combination with serum potentiates the stimulated activity of phospholipase D in human neutrophils via CD14.","authors":"K Yasui, E L Becker, R I Sha'afi","doi":"10.3109/09687689309150255","DOIUrl":"https://doi.org/10.3109/09687689309150255","url":null,"abstract":"The addition of fMet-Leu-Phe or phorbol 12-myristate 13-acetate to human neutrophils stimulates phospholipase D activity as evidenced by the release of phosphatidic acid and the generation of diacylglycerol, and in the presence of ethanol the formation of phosphatidyl ethanol. The activation of phospholipase D by either the chemotactic factor or active phorbol ester is inhibited by the tyrosine kinase inhibitor erbstatin. The fMet-Leu-Phe-induced stimulation of this enzyme is greatly potentiated in cells which have been preincubated with low concentrations of lipopolysaccharide and serum. The presence of serum is essential for the potentiation by low concentrations of lipopolysaccharide. Moreover, the monoclonal antibody MY4(IgG2b) against CD14 inhibits the potentiation by the low concentration of lipopolysaccharide. These data suggest three important points. First, a tyrosine kinase step is necessary for the activation of phospholipase D. This suggests that the phospholipase D enzyme needs to be phosphorylated on tyrosine residues to be activated. Second, low concentrations of lipopolysaccharide, in the presence of serum, can potentiate the stimulated activity of this enzyme. Third, the priming action of the lipopolysaccharide-serum complex is mediated by CD14.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 2","pages":"81-9"},"PeriodicalIF":0.0,"publicationDate":"1993-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18692505","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: 5

Hormonal regulation of gap junction proteins and estrogen receptor activation factors in the rat uterus. 大鼠子宫间隙连接蛋白和雌激素受体激活因子的激素调节。

Membrane biochemistry Pub Date : 1993-04-01 DOI: 10.3109/09687689309150259

P Anuradha, R V Thampan

引用次数: 5

Effects of methadone use during pregnancy on human placental opioid receptors. 妊娠期美沙酮对人胎盘阿片受体的影响。

Membrane biochemistry Pub Date : 1993-04-01 DOI: 10.3109/09687689309150256

M S Ahmed, B Cemerikic, S Mou, A Agbas

引用次数: 6

Effects of diabetes mellitus on structural and functional properties of erythrocyte membranes. 糖尿病对红细胞膜结构和功能特性的影响。

Membrane biochemistry Pub Date : 1993-04-01 DOI: 10.3109/09687689309150254

R A Rabini, P Fumelli, R Staffolani, L Mazzanti, A Pugnaloni, G Biagini, E Faloia, R De Pirro

{"title":"Effects of diabetes mellitus on structural and functional properties of erythrocyte membranes.","authors":"R A Rabini, P Fumelli, R Staffolani, L Mazzanti, A Pugnaloni, G Biagini, E Faloia, R De Pirro","doi":"10.3109/09687689309150254","DOIUrl":"https://doi.org/10.3109/09687689309150254","url":null,"abstract":"Diabetic patients present alterations in the activity of a number of enzymes of the plasma membrane. The aim of this study was to verify if the modifications of the enzymatic activities in diabetes mellitus are associated with structural alterations of the cellular membrane. By means of the freeze-fracturing technique, we studied the structure of erythrocyte membranes from 15 insulin-dependent diabetic patients (24-43 years) and 15 age-matched healthy subjects (26-47 years). The kinetic properties of the Na+/K(+)-ATPase of the same membranes were also investigated. The Na+/K(+)-ATPase of the erythrocyte plasma membrane shows an uncompetitive inhibition in the diabetic subjects. As for the freeze-fracturing results, the intramembrane particles of the erythrocyte membranes from diabetic patients appear more clustered with respect to those obtained from controls. The uncompetitive inhibition of the enzyme suggests the presence of conformational modifications of the protein. This hypothesis is supported by the freeze-fracture results which indicate that the integral protein constituents of the membrane in diabetes tend to aggregate. Modifications of the interactions between the enzymatic subunits and the membrane lipid environment might be at the basis of the Na+/K(+)-ATPase alteration in diabetes.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 2","pages":"71-9"},"PeriodicalIF":0.0,"publicationDate":"1993-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19380172","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: 20

Isolation of lactose permease mutants which recognize arabinose. 识别阿拉伯糖的乳糖渗透酶突变体的分离。

Membrane biochemistry Pub Date : 1993-01-01 DOI: 10.3109/09687689309150253

V C Goswitz, R J Brooker

{"title":"Isolation of lactose permease mutants which recognize arabinose.","authors":"V C Goswitz, R J Brooker","doi":"10.3109/09687689309150253","DOIUrl":"https://doi.org/10.3109/09687689309150253","url":null,"abstract":"In the present study lactose permease mutants were isolated which recognize the monosaccharide, L-arabinose. Although the wild-type permease exhibits a poor recognition for L-arabinose, seven independent mutants were identified by their ability to grow on L-arabinose minimal plates. When subjected to DNA sequencing, it was found that all seven of these mutants were single-site mutations in which alanine 177 was changed to valine. The wild type and valine 177 mutant were then analyzed with regard to their abilities to recognize and transport monosaccharides and disaccharides. Free L-arabinose was shown to competitively inhibit [14C]-lactose transport yielding a Ki value of 121 mM for the Val177 mutant and a much higher value of 320 mM for the wild-type. Among several monosaccharides, D-glucose as well as L-arabinose inhibited lactose transport in the Val177 mutant to a significantly greater extent, while D-arabinose and D-xylose only caused a slight inhibition. On the other hand, kinetic studies with sugars which are normally recognized by the wild-type permease such as [14C]-galactose and [14C]-lactose revealed that the Val177 mutant and wild-type strains had similar transport characteristics for these two sugars. Overall, these results are consistent with the notion that the Val177 substitution causes an enhanced recognition for particular sugars (i.e. L-arabinose) but does not universally affect the recognition and unidirectional transport for all sugars. This idea is further supported by the observation that site-directed mutants containing isoleucine, leucine, phenylalanine, or proline at position 177 also were found to possess an enhanced recognition for L-arabinose.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 1","pages":"61-70"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19491597","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: 21

Synthesis of N-(4'-pyridoxyl)sphingosine and its uptake and metabolism by isolated cells. N-(4′-吡哆氧基)鞘氨醇的合成及其在离体细胞中的摄取和代谢。

Membrane biochemistry Pub Date : 1993-01-01 DOI: 10.3109/09687689309150252

Z Zhang, E Smith, S M Surowiec, A H Merrill, D B McCormick

{"title":"Synthesis of N-(4'-pyridoxyl)sphingosine and its uptake and metabolism by isolated cells.","authors":"Z Zhang, E Smith, S M Surowiec, A H Merrill, D B McCormick","doi":"10.3109/09687689309150252","DOIUrl":"https://doi.org/10.3109/09687689309150252","url":null,"abstract":"N-(4'-pyridoxyl)sphingosine was synthesized and characterized as a stable compound for specialized delivery of a bioactive lipid. It was found to be facilely taken up by hepatocytes although by a mechanism more typical for lipids than the one used by natural vitamin B6. Some of the N-(4'-pyridoxyl)sphingosine was metabolically acted upon inside the cell to release pyridoxal 5'-phosphate and sphingosine, but formation of pyridoxal 5'-phosphate from the synthetic compound was poor compared with natural vitamin forms of B6, which may partly be due to entrapment within cell membranes and to constraints at the level of cytosolic pyridoxal kinase which is responsible for phosphorylation of the vitamin. Unlike the parent long-chain base, the B6 conjugate was not particularly cytotoxic. Furthermore, the compound was neither an activator nor inhibitor of the respiratory burst of human neutrophils. These findings identify N-(4'-pyridoxyl)sphingosine as an interesting tool for studies of the cellular transport, metabolism, and functions of both vitamin B6 and sphingosine.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 1","pages":"53-9"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150252","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19491595","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

Factors affecting the stability of detergent-solubilized cholinephosphotransferase and ethanolaminephosphotransferase. 影响洗涤剂溶化胆碱磷酸酶和乙醇胺磷酸酶稳定性的因素。

Membrane biochemistry Pub Date : 1993-01-01 DOI: 10.3109/09687689309150251

A Mancini, R Roberti, L Binaglia, A el Missiri, L Freysz

{"title":"Factors affecting the stability of detergent-solubilized cholinephosphotransferase and ethanolaminephosphotransferase.","authors":"A Mancini, R Roberti, L Binaglia, A el Missiri, L Freysz","doi":"10.3109/09687689309150251","DOIUrl":"https://doi.org/10.3109/09687689309150251","url":null,"abstract":"Cholinephosphotransferase (CPT) and ethanolaminephosphotransferase (EPT) are the enzymes catalyzing the last step of the de novo pathway for phosphatidylcholine and phosphatidylethanolamine synthesis, respectively. A major limitation for the complete characterization of the reactions catalyzed by the two enzymes derives from their poor stability in detergent-containing buffers. CPT is heavily inactivated, when native membranes are solubilized using a series of detergents, whereas EPT activity is better preserved during solubilization. An investigation of the factors which could play a role in preserving both enzymes from inactivation was carried out. The dramatic loss of enzymatic activities occurring upon dilution of solubilized membranes with detergent-containing buffers can be reduced by supplementing the dilution medium with phospholipids. The addition of Mn2+ ions to the dispersion buffer increases the stability of both enzymes. The procedure previously described for solubilizing EPT from rat brain microsomes has been modified on the basis of this evidence. Microsomes were solubilized in buffered detergent solutions containing Mn2+ ions and both CPT and EPT were partially purified in their active form by anion-exchange chromatography.","PeriodicalId":18448,"journal":{"name":"Membrane biochemistry","volume":"10 1","pages":"43-52"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/09687689309150251","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"19375154","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: 4