Academic literature on the topic 'Ionic detergents'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Ionic detergents.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Ionic detergents"
1
Cham, B. E., P. Roeser, and A. Nikles. "Effects of non-ionic and anionic detergents on lipid-associated tissue ferritin." Clinical Chemistry 34, no. 1 (1988): 152–54. http://dx.doi.org/10.1093/clinchem/34.1.152.
Full textAbstract:
Abstract Lipid-associated ferritin from homogenates of guinea pig liver is released from its conjugate(s) by incubation with the non-ionic detergents Triton X-100 and Nonidet P-40 but not by incubation with the anionic detergent deoxycholate. The amount of lipid-associated ferritin released from its conjugate(s) depends on the concentration of the non-ionic detergents. At a final non-ionic detergent concentration of about 20 g/L, all lipid-associated ferritin is released from its conjugate(s) in a liver homogenate. The amount released is identical with the amount of the lipid-associated ferritin obtained by extraction of the same liver homogenate with a mixture of butanol and diisopropyl ether.
2
Kurisu, Toshikatsu, Hiroyasu Taguchi, Bela Paal, Nan Yang та Wilfred L. F. Armarego. "Glyceryl-ether Monooxygenase [EC 1.14.16.5J Part VII Effects of Alkyl Phosphocholines and Acyl L-α-lyso-Phosphatidylcholines Detergents on Enzyme Activity". Pteridines 5, № 3 (1994): 95–101. http://dx.doi.org/10.1515/pteridines.1994.5.3.95.
Full textAbstract:
Summary The effects of the ionic detergents dodecyl, tetradecyl, hexadecyl and octadecyl phosphocholines, and dodecanoyl, tetradecanoyl, hexadecanoyl and octadecanoyl L-a-lyso-phosphatidylcholines on the enzyme activity of glyceryl-ether monooxygenase are reported. All these detergents inhibit the monooxygenase at concentrations above a threshold value which is above the relative critical micelle concentrations implying that the micelles interact passively with the microsomal membrane below the threshold concentration. The kinetics of inhibition by the C14 and C16 detergents above the threshold concentrations have been selected for study and are found to be competitive with apparent Ki values in the range 316-365 IlM. The apparent Km and Vmax values for RS-batyl alcohol with 6-MePH4 as cofactor in the presence of the choline detergents (at or below the threshold inhibiting concentrations) are in the range 24-44 μM and 46-64 nrnoles/ min.mg of monooxygenase protein respectively. These data are compared and discussed with data reported for the monooxygenase in the presence of the non-ionic detergent Mega-10.
3
Lee, Joshua Y., Katherine M. Selfridge, Eric M. Kohn, Timothy D. Vaden, and Gregory A. Caputo. "Effects of Ionic Liquid Alkyl Chain Length on Denaturation of Myoglobin by Anionic, Cationic, and Zwitterionic Detergents." Biomolecules 9, no. 7 (2019): 264. http://dx.doi.org/10.3390/biom9070264.
Full textAbstract:
The unique electrochemical properties of ionic liquids (ILs) have motivated their use as solvents for organic synthesis and green energy applications. More recently, their potential in pharmaceutical chemistry has prompted investigation into their effects on biomolecules. There is evidence that some ILs can destabilize proteins via a detergent-like manner; however, the mechanism still remains unknown. Our hypothesis is that if ILs are denaturing proteins via a detergent-like mechanism, detergent-mediated protein unfolding should be enhanced in the presence of ILs. The properties of myoglobin was examined in the presence of a zwitterionic (N,N-dimethyl-N-dodecylglycine betaine (Empigen BB®, EBB)), cationic (tetradecyltrimethylammonium bromide (TTAB)), and anionic (sodium dodecyl sulfate (SDS)) detergent as well as ILs based on alkylated imidazolium chlorides. Protein structure was measured through a combination of absorbance, fluorescence, and circular dichroism (CD) spectroscopy: absorbance and CD were used to monitor heme complexation to myoglobin, and tryptophan fluorescence quenching was used as an indicator for heme dissociation. Notably, the detergents tested did not fully denature the protein but instead resulted in loss of the heme group. At low IL concentrations, heme dissociation remained a traditional, cooperative process; at high concentrations, ILs with increased detergent-like character exhibited a more complex pattern, which is most likely attributable to micellization of the ionic liquids or direct denaturation or heme dissociation induced by the ILs. These trends were consistent across all species of detergents. 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence was further used to characterize micelle formation in aqueous solutions containing detergent and ionic liquid. The dissociation thermodynamics show that EBB- and TTAB-induced dissociation of heme is not significantly impacted by room temperature ionic liquids (RTILs), whereas SDS-induced dissociation is more dramatically impacted by all RTILs examined. Together, these results indicate a complex interaction of detergents, likely based on headgroup charge, and the active component of RTILs to influence heme dissociation and potentially protein denaturation.
4
Claffey, David J., Jeffrey D. Meyer, Robert Beauvais, et al. "Long chain arginine esters: A new class of cationic detergents for preparation of hydrophobic ion-paired complexes." Biochemistry and Cell Biology 78, no. 1 (2000): 59–65. http://dx.doi.org/10.1139/o99-072.
Full textAbstract:
The ability of stoichiometric amounts (based on charged groups) of ionic detergents to bind to oppositely charged ionic compounds has been recently reviewed. These hydrophobic ion-paired (HIP) complexes display altered solubility properties. Most of the work to date on HIP compelxes has focused on basic drugs and anionic detergents. It would be extremely useful to extend this approach to acidic compounds, including DNA and RNA. However, most cationic detergents are relatively toxic. It is hypothesized that detergents constructed from naturally occurring or well tolerated components, coupled by labile linkages, will be less toxic and still able to form strong HIP complexes. This study describes the synthesis and characterization of long chain alkyl esters of arginine. This class of cationic detergents, which have not been reported previously, are less cytotoxic than alkyltrimethylammonium detergents, possibly making them more acceptable in drug delivery applications. These arginine esters exhibit detergent-like properties. For example, the dodecyl ester of arginine has a critical micelle concentration of 0.07 mM, while being approximately 5-10 fold less toxic than tetradecyltrimethylammonium bromide. The arginine dodecyl ester forms stable HIP complexes with plasmid DNA. The complex is sufficiently stable to allow some modest level of transfection with Cos-7 cells in a time- and concentration-dependent fashion. This work demonstrates that arginine-based cationic detergents are effective ion-pairing agents, appear to be less toxic than alkyltrimethylammonium compounds, and form stable complexes with DNA.
5
SOLOMON, Keith R., Mark A. MALLORY, and Robert W. FINBERG. "Determination of the non-ionic detergent insolubility and phosphoprotein associations of glycosylphosphatidylinositol-anchored proteins expressed on T cells." Biochemical Journal 334, no. 2 (1998): 325–33. http://dx.doi.org/10.1042/bj3340325.
Full textAbstract:
Glycosylphosphatidylinositol (GPI)-anchored proteins are poorly solublized in non-ionic detergents such as Triton X-100 and Nonidet P40, but are easily solublized by detergents with high critical micelle concentrations such as octylglucoside. This solubility profile has been suggested to be due to the localization of GPI-anchored proteins to lipid microdomains rich in cholesterol and sphingolipids. Additionally, GPI-anchored proteins expressed on haemopoietic cells have been shown to associate with src-family tyrosine kinases and heterotrimeric G proteins. Despite these observations, the non-ionic detergent insolubility of GPI-anchored proteins on haemopoietic cells has not been quantified nor has a relationship between the non-ionic detergent insolubility of these proteins and their association with signal-transduction molecules been identified. Here we show that GPI-anchored proteins found on T-cell tumours and activated T cells, although significantly more insoluble then transmembrane proteins, are not uniform in their detergent insolubility. Whereas CD59 was between 4% and 13% soluble, CD48 was between 13% and 25% soluble, CD55 was between 20% and 30% soluble, and CD109 was between 34% and 75% soluble. The ability of these GPI-anchored proteins to associate with phosphoproteins was correlated with their detergent insolubility: the more detergent-insoluble that a GPI-anchored protein was, the greater the level of phosphoprotein associations. These experiments reveal a relationship between non-ionic detergent insolubility and association with signal-transduction molecules and suggest a cause-and-effect relationship between these two properties. In total, these experiments support the hypothesis that the association of GPI-anchored proteins with signalling molecules is due to their sorting to lipid microdomains.
6
Ismail, Alnashir A., and Roger Hand. "Membrane D2 T antigen: characterization and comparison with its nuclear counterpart." Biochemistry and Cell Biology 66, no. 8 (1988): 928–34. http://dx.doi.org/10.1139/o88-106.
Full textAbstract:
Up to 40% of membrane T antigen (D2 T antigen) produced by the adenovirus 2–simian virus 40 hybrid, Ad2+D2, remained tightly associated with membranes under alkaline conditions up to pH 11.5. The antigen could not be totally solubilized by treatment with ionic detergents, nonionic detergents, or both. These properties are characteristic of integral membrane proteins. Sephacryl S-300 chromatography in high salt in the presence of Brij-99 showed that the nuclear form of D2 T antigen was dissociated to low molecular weight species, while the membrane form eluted as a complex of high molecular weight. The membrane form, therefore, is able to bind more detergent than the nuclear form, indicating a difference in supramolecular structure.
7
Brinkworth, Craig S., and David J. Bourne. "Selected Non-Ionic Biological Detergents Enhance Signal Intensity of Intact Bovine Serum Albumin by Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry." European Journal of Mass Spectrometry 13, no. 5 (2007): 311–19. http://dx.doi.org/10.1255/ejms.886.
Full textAbstract:
Recently, we showed that the signal intensity of intact protein by matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry measurement can be enhanced at least an order of magnitude by the addition of Tween80 to the analyte solution. We did not ascertain whether this effect was limited to Tween80 or if it was more universal of biological detergents. This paper discusses our investigations into this question. A variety of chemically diverse detergents were added to analyte solutions containing bovine serum albumin (BSA) to determine whether there was significant signal enhancement. The addition of Tween20, Tween80, Triton X-100 and Triton X-114 improved the attainable sensitivity of intact protein MALDI mass spectrometry compared to spectra acquired without detergent. In some cases there was considerable improvement in signal—for example, with Triton X-100 two charge states (the +1 and +2) of BSA (3.9 fmol) could easily be observed. Another advantage of this process is that the detergent can be added directly to the matrix solution reducing sample handling and preparation time. We propose this phenomenon results from the ability of these detergents to increase the solubility of the protein via hydrophobic and hydrophilic interactions between the detergent and protein. The increased solubility allows for more uniform deposition of the analyte/matrix mixtures producing an evenly distributed layer of analyte especially useful for data acquisition using an automated laser firing sequence.
8
Yakovlev, A. A., T. A. Druzhkova, A. B. Guekht, and N. V. Gulyaeva. "Sensitivity of Extracellular Vesicles from Human Blood Serum to Various Detergents." Biomedical Chemistry: Research and Methods 3, no. 4 (2020): e00143. http://dx.doi.org/10.18097/bmcrm00143.
Full textAbstract:
Blood exosomes and microvesicles, collectively known as small extracellular vesicles (sEV), are vesicles about 100-150 nm in size. Small EV are involved in various aspects of signaling in the body; in addition, they can serve as markers of various pathologies. For biochemical studies, vesicle solubilization is often required. We tested the ability of various detergents to dissolve membranes of the sEV. Small EV were isolated from the blood serum of healthy volunteers by gel filtration on Sepharose CL-2B and tried to solubilize them using the anionic detergent DOC (sodium deoxycholate), non-ionic detergent Brij 35 (polyoxyethyleneglycol dodecyl ether), zwitterionic detergent CHAPS (3 - [(3-chloramidopropyl) dimethylammonio] -1-propanesulfonate), and cationic detergent CTAB (cetyl trimethylammonium bromide). The concentration of sEV in the solution was determined by dynamic light scattering. We find DOC is the most effective for sEV solubilization.
9
Amtmann, Eberhard, Karin Müller-Decker, Angela Hoss, Gunnar Schalasta, Clemens Doppler, and Gerhard Sauer. "Synergistic antiviral effect of xanthates and ionic detergents." Biochemical Pharmacology 36, no. 9 (1987): 1545–49. http://dx.doi.org/10.1016/0006-2952(87)90124-9.
Full text
10
Shogomori, H., and D. A. Brown. "Use of Detergents to Study Membrane Rafts: The Good, the Bad, and the Ugly." Biological Chemistry 384, no. 9 (2003): 1259–63. http://dx.doi.org/10.1515/bc.2003.139.
Full textAbstract:
Abstract Eukaryotic cell membranes contain microdomains called lipid rafts, which are cholesterol-rich domains in which lipid acyl chains are tightly packed and highly extended. A variety of proteins associate preferentially with rafts, and this raft association is important in a wide range of functions. A powerful and widely used method for studying lipid rafts takes advantage of their insolubility in non-ionic detergents. Here we describe the basis of detergent insolubility, and review strengths, limitations, and unresolved puzzles regarding this method.
Dissertations / Theses on the topic "Ionic detergents"
1
Yihwa, Chang. "Reatividade química e fotoquímica em agregados de tensoativos em água/acetonitrila." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/46/46132/tde-26092014-123704/.
Full textAbstract:
Neste trabalho, estudou-se o efeito da adição de acetonitrila na reatividade química em soluções micelares do detergente aniônico dodecil sulfato de sódio (SDS) e do detergente catiônico brometo de hexadeciltrimetilamônio (CTAB) e em agregados supramoleculares do sal biliar, colato de sódio (NaCh). Os sistemas utilizados para estudar a reatividade química na presença de acetonitrila foram: (a) fotorreatividade do estado excitado triplete de n-butil-3-nitrofenil éter (em SDS); (b) reação de hidrólise ácida do 2-(p-octoxifenil)-1,3-dioxolano no estado fundamental (em SDS); (c) constante de incorporação do co-íon N-dodecil-4-cianopiridínio (em CTAB); (d) a protonação/desprotonação do ácido fraco 4-metil-7-hidroxiflavílio, tanto no estado excitado como no estado fundamental (em SDS); e (e) a supressão dos estados excitados de 1-etilnaftaleno e 1-(1-naftil)-etanol (em NaCh). As modificações na estruturação do agregado micelar e nas propriedades do meio aquoso, provocadas pela presença de acetonitrila, fazem com que as moléculas orgânicas e os íons saiam mais rapidamente do agregado para a fase aquosa. As mudanças que ocorrem com a micela e com a partição de solutos diminuem o efeito catalítico da micela sobre a reatividade química. Os agregados de sal biliar possuem dois sítios distintos de ligação de solutos e a concentração mínima de sal biliar necessária para formar esses dois sítios depende da concentração de acetonitrila. Em concentrações de acetonitrila acima de 10 %, ocorre somente a formação de agregados com sítio primário, enquanto que acima de 30 % os agregados se desfazem por completo. Em baixas concentrações de acetonitrila (até aproximadamente 10 %), a dinâmica de dissociação de solutos do sítio secundário do agregado de sal biliar não modifica muito, enquanto que a velocidade de saída de solutos do sítio primário aumenta com a presença da acetonitrila. Desse modo, a acetonitrila pode ser empregada para acelerar a saída de uma espécie, tal como um intermediário reativo, do agregado primário, facilitando a aplicação de agregados de sal biliar como micro-reatores com dois sítios distintos de reação.<br>This work reports a study of the effect of the addition of acetonitrile on chemical reactivity in micellar solutions of the anionic detergent sodium dodecyl sulfate (SDS) and the cationic detergent hexadecyltrimethylammonium bromide (CTAB) and in supramolecular aggregates of the bile salt sodium cholate (NaCh). The systems employed in the study of chemical reactivity in the presence of acetonitrile were: (a) photoreactivity of the excited triplet state of N-butyl-3-nitrophenyl ether in SDS; (b) the acid catalyzed of 2-(p-octoxy-nitrophenyl)-1,3-dioxolane in the ground state in SDS; (c) incorporation of the coion N-dodecyl-4-cyanopyridine in CTAB; (d) protonation/deprotonation of the weak acid of the 4-methyl-7-hydroxyflavilium ion in the ground and excited state in SDS; and (e) quenching of the excited state of 1-ethylnaphthalene and 1-(1-naphthyl)-ethanol in NaCh. The modifications of the structure of the micellar aggregate and of the properties of the bulk aqueous phase induced by acetonitrile result in a faster rate of exit of organic molecules and ions from the aggregate into the aqueous phase. The changes that occur in the micelle and in the partitioning of solutes tend to diminish the catalytic effect of micelles on chemical reactivity. Bile salt aggregates possess two distinct sites for solubilization of solutes and the minimum concentration of bile salt necessary for the formation of these two sites depends on the concentration of acetonitrile. At acetonitrile concentrations above 10 %, only aggregates with the primary solubilization site are formed and, above 30 %, the aggregates are completely disrupted. At low acetonitrile concentrations (below 10 %), the dynamics of dissociation of solutes from the secondary site of bile salt aggregates changes very little, while the rate of exit of solutes from the primary site increases in the presence of acetonitrile. Thus, acetonitrile can be employed to accelerate the rate of exit of species such as reactive intermediates, facilitating the application of bile salt aggregates as two-reaction-site microreactors.
2
Devlin, Carolyn. "Ionic liquids for applications in the detergent industry." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601358.
Full textAbstract:
Bleach activators are used in combination with hydrogen peroxide in laundry detergents across the globe to improve the bleaching performance at lower wash temperatures. There are four main activators which are significant on the world market, all of which are solid at room temperature. In household detergents, the incorporation of bleach activators in liquid detergent products has been limited due to incompatibility with other components in solution. In this work, more than 30 novel ionic liquids derived from known and commercially available bleach activators were prepared. The bleach activators, which were available as sodium salts, underwent a facile metathesis reaction with chloride compounds in propanone to form the ionic liquids. Ionic liquids were formed using several different types and sizes of cation, with product physical states varying from liquid or gel to crystalline or waxy so lids. As expected from lattice energy theory, larger and unsymmetrical cations formed products with the lowest melting points, several of which were liquid at room temperature. All novel ionic liquid bleach activators were characterised by several techniques including NMR analysis, microanalysis and ES Mass spectroscopy. As this is the first time bleach activators have been incorporated in ionic liquids, it was unknown what affect this would have on the bleaching ability of the activators. Solution bleaching reactions using the dye Tropaeolin 0 were performed . The dye concentration of the solution was measured by electronic absorption spectroscopy over time. It was found that in most cases the ionic liquid did not have a negative impact on bleaching. One exception was pyridinium cations, the presence of which appeared to prevent the bleaching reaction from occurring at all. Cations which had surface-active properties were found to increase the bleaching rate.
Book chapters on the topic "Ionic detergents"
1
Murata, Yoshio, Makoto Ōkawauchi, Hideo Kawamura, Gohsuke Sugihara, and Mitsuru Tanaka. "Interaction Between Ionic Detergents and a Protein." In Surfactants in Solution. Springer US, 1986. http://dx.doi.org/10.1007/978-1-4615-7981-6_25.
Full text
2
Frank, Gerhard. "New Aspects in Isocratic HPLC Separation of Phenylthiohydantoin Amino Acids Through the Application of Ionic Detergents." In Methods in Protein Sequence Analysis. Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-73834-0_15.
Full text
3
Ghanotakis, Demetrios F., and Charles F. Yocum. "Characterization of a Photosystem II Reaction Center Complex Isolated by Exposure of PSII Membranes to a Non-Ionic Detergent and High Concentrations of NaC1." In Excitation Energy and Electron Transfer in Photosynthesis. Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3527-3_37.
Full text
4
MISHUSTINA, N. E., D. B. VAKHMISTROV, O. A. ZVERKOVA, and E. Yu KOROLEVA. "The Effect of Non-Ionic & Ionic Detergents on the Growth of Cucumber Seedlings." In Plant Roots and their Environment. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-444-89104-4.50067-0.
Full text
5
Kirchner, Michele, Joseph Fernandez, Quazi Aga Shakey, Farzin Gharahdaghi, and Sheenah M. Mische. "Enzymatic digestion of PVDF-bound proteins: A survey of sixteen non-ionic detergents." In Techniques in Protein Chemistry. Elsevier, 1996. http://dx.doi.org/10.1016/s1080-8914(96)80032-9.
Full text
6
Swiderek, Kristine M., Michael L. Klein, Stanley A. Hefta, and John E. Shively. "Strategies for the removal of ionic and non-ionic detergents from protein and peptide mixtures for on- and off-line liquid chromatography mass spectrometry (LCMS)." In Techniques in Protein Chemistry. Elsevier, 1995. http://dx.doi.org/10.1016/s1080-8914(06)80034-7.
Full text
7
Reiss-Husson, F., and D. Picot. "Crystallization of Membrane Proteins." In Crystallization of Nucleic Acids and Proteins. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780199636792.003.0013.
Full textAbstract:
Crystallization of membrane proteins is one of the most recent developments in protein crystal growth; in 1980, for the first time, two membrane proteins were successfully crystallized, bacteriorhodopsin (1) and porin (2). Since then, a number of membrane proteins (about 30) yielded three-dimensional crystals. In several cases, the quality of the crystals was sufficient for X-ray diffraction studies. The first atomic structure of a membrane protein, a photosynthetic bacterial reaction centre, was described in 1985 (3), followed by the structure of about ten other membrane protein families. Crystallization of membrane proteins is now an actively growing field, and has been discussed in several recent reviews (4-8). The major difficulty in the study of membrane proteins, which for years hampered their crystallization, comes from their peculiar solubility properties. These originate from their tight association with other membrane components, particularly lipids. Indeed integral membrane proteins contain hydrophobic surface regions buried in the lipid bilayer core, as well as hydrophilic regions with charged or polar residues more or less exposed at the external faces of the membrane. Disruption of the bilayer for isolating a membrane protein can be done in various ways: extraction with organic solvents, use of chaotropic agents, or solubilization by a detergent. The last method is the most frequently used, since it maintains the biological activity of the protein if a suitable detergent is found. This chapter will be restricted to specific aspects of three-dimensional crystallizations done in micellar solutions of detergent. In some cases, it is possible to separate soluble domains from the membrane protein either by limited proteolysis or by genetic engineering. Such protein fragments can then be treated as soluble proteins and so will not be discussed further in this chapter. We refer to Chapter 12 and the review by Kühlbrandt (9) for the methodology of two-dimensional crystallization used for electron diffraction. The general principles discussed in this book for the crystallization of soluble biological macromolecules apply for membrane proteins; the protein solution must be brought to supersaturation by modifying its physical parameters (concentrations of constituents, ionic strength, and so on), so that nucleation may occur.
Conference papers on the topic "Ionic detergents"
1
Bienz, D., T. Wager, and K. J. Clemetson. "ISOLATION AND CHARACTERIZATION OF HUMAN PLATELET MEMBRANE GLYCOPROTEINS Ia AND IIa." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643910.
Full textAbstract:
Glycoproteins (GP) Ia and IIa are relatively minor components of the platelet surface with similar molecular properties. Nieuwenhuis et al. (Nature 319, 470-72, 1985) described a patient whose platelets show no response to collagen. The correlating lack of GPIa in the platelets of this patient suggests this glycoprotein being the receptor for collagen. Santoro (Cell, 46, 913-20, 1986) described a 160 kDa glycoprotein that binds to collagen in the presence of MG2 + and is possibly identical with GPIa. The role of GPIIa is still unknown but a similar molecule has also been found on endothelial cells. It has been suggested that GPIa and GPIIa are complexed with a further membrane component GPIc. The two glycoproteins show only slight difference in molecular weight, isoelectric point and in their affinity for various lectins. As a result they coisolate using most separation techniques.GPIa is usually associated with the cytoskeleton while GPIIa is mostly found in the soluble phase. GPIa is dissociated from the cytoskeleton by addition of 2% SDS (final conc.) and sonication. Performing Triton X-114 phase partition, GPIIa is found in the detergent phase. After the detergents of the GPIa and GPIIa enriched protein solutions are exchanged with the non-ionic octanoyl-N-methyl glucamide, the glycoproteins are further purified by affinity chromatography on wheat germ agglutinin-Sepharose followed by Lens culinaris lectin-Sepharose both of which bind GPIa and GPIIa. A major contaminant during the purification is GPIb. Final purification of GPIa and GPIIa was obtained by preparative SDS-PAGE using electroelution into a membrane trap. Latest results show an enrichment of GPIa and a lack of GPIb in pseudopodes, isolated by the method of Rotman et al. (Proc. Natl. Acad. Sci. USA, 4357-61, 1982).
2
Levin, G. E., and L. Santel. "ASSOCIATION OF PLASMINOGEN ACTIVATOR INHIBITOR(PAI-1) WITH THE MEMBRANE AND EXTRACELLULAR MATRIX OF HUMAN ENDOTHELIAL CELLS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644435.
Full textAbstract:
The cytosol, membrane-containing, and extracellular matrix(ECM) fractions of cultured human endothelial cells were isolated and analyzed for the presence and levels of PAI-1. Cells(4×106) released intact from the substratum had 70% (2.85±0.16 units)of their total inhibitor activity in the soluble portion of cell homogenate with the remaining activity(1.26±0.30 units) in the 100,000xg pellet.The ECM contained over twice as much activity as the total cellular inhibitor(9.82±0.35 units).Similar results were obtained with ECM after cell removal by 0.5% Na deoxycholate and hypotonic buffer treatment. Analysis of all three samples by SDS-PAGE and reverse fibrin autography showed inhibitor activity at an identical position on the gel corresponding to Mr=46000.Immunoblot analysis demonstrated that this inhibitor activity represented PAI-1. Inhibitor was not removed from the membrane by treatment with high salt, EDTA,divalent cations, low ionic strength buffer or sonication but was dissociated in the presence of detergents, guanidine HC1, or high pH. In contrast, ECM-associated PAI-1 was not affected by any of these treatments. Pulse-chase experiments indicated that the inhibitor was associated only transiently with the ECM in the presence of cells. None of the PAI-1 deposited during the labeling period was observed after 24 hrs. Incubation of the isolated ECM with protolytically active tPA resulted in a decline in the intensity of the Mr=46000 inhibitor band and the appearance of a Mr=44000 band and a Mr=110000 tPA-inhibitor complex band. Both of these bands were also found in the supernatent. The Mr=44000 band represented PAI-1 as shown by immunoprecipitation studies, although it did not contain anti-tPA activity.Thus, ECM-bound PAI-1 is susceptible to cleavage and release by tPA but does not in all cases form a stable complex with the protease. Elastase had a similar effect: following incubation, all of the PAI-1 was released from the ECM into the supernatent and was converted to the Mr=44000 inhibitor form. Collagenase, heparinase, and chondroitinase ABC had no effect. Therefore, PAI-1 is susceptible to inactivation and release from ECM by several proteases.