Large vesicle contamination in small, unilamellar vesicles

Barrow, D.A.; Lentz, Barry R.

doi:10.1016/0005-2736(80)90153-4

Cited by 68 publications

(34 citation statements)

References 11 publications

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“…First, for a homogeneous dispersion of vesicles (both chemically and in terms of vesicle size), the molar turbidity depends linearly on vesicle size (Ohsawa et al, 1985;Almog et al, 1986) and can therefore be used for size-evaluation, although, it is clear that for any given system the relationship between vesicle diameter and specific turbidity must be studied before this method can be employed. Secondly, the dependence of turbidity on wavelength enables the detection of the presence and the amount of large multilamellar vesicles in dispersions of small ones (Barrow and Lentz, 1980).…”

Section: B C D T E R Counter the Coultermentioning

confidence: 99%

“…These have been reviewed by Bangham et al (1974), Bangham (1982), and Szoka and Papahadjopoulos (1980). As discussed by these authors, the commonly used sonication by a probe sonicator (Huang, 1969) has the advantage of being fast and reproducible (Papahadjopoulos and Watkins 1967;Johnson et al, 1971; Barrow and Lentz, 1980). The major shortcomings of probe sonication are that it often results in contamination of the dispersion by metal particles and possibly ions, and, unlike the bath sonicator, it cannot be used in closed systems and therefore is more difficult to control in terms of the temperature.…”

Section: Liposomes: Preparation Characterization and Preservation 407mentioning

confidence: 99%

“…The major shortcomings of probe sonication are that it often results in contamination of the dispersion by metal particles and possibly ions, and, unlike the bath sonicator, it cannot be used in closed systems and therefore is more difficult to control in terms of the temperature. The development of high-powered cup horn sonifiers has made bath-type sonicators almost as effective as the probe sonicators in disrupting MLVs to SUVs (Barrow and Lentz, 1980), making this technique very promising for many uses of liposomes.…”

Section: Liposomes: Preparation Characterization and Preservation 407mentioning

confidence: 99%

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Liposomes: Preparation, Characterization, and Preservation

Lichtenberg

Barenholz

1988

Methods of Biochemical Analysis

244

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Section: B C D T E R Counter the Coultermentioning

confidence: 99%

Section: Liposomes: Preparation Characterization and Preservation 407mentioning

confidence: 99%

Section: Liposomes: Preparation Characterization and Preservation 407mentioning

confidence: 99%

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Liposomes: Preparation, Characterization, and Preservation

Lichtenberg

Barenholz

1988

Methods of Biochemical Analysis

244

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“…32 Large multilamellar vesicles were prepared by evaporating chloroform from the desired phospholipid, resuspending the lipids in methylene chloride, and reevaporating 3 times under argon. Lipids were resuspended as vesicles by gently swirling Tris-buffered saline over the dried lipid.…”

Section: Phospholipid Vesiclesmentioning

confidence: 99%

A membrane-interactive surface on the factor VIII C1 domain cooperates with the C2 domain for cofactor function

Lü

Pipe

Miao

et al. 2011

Blood

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Factor VIII binds to phosphatidylserine (PS)-containing membranes through its tandem, lectin-homology, C1 and C2 domains. However, the details of C1 domain membrane binding have not been delineated. We prepared 4 factor VIII C1 mutations localized to a hypothesized membrane-interactive surface (Arg2090Ala/Gln2091Ala, Lys2092Ala/Phe2093Ala, Gln2042Ala/Tyr2043Ala, and Arg2159Ala). Membrane binding and cofactor activity were measured using membranes with 15% PS, mimicking platelets stimulated by thrombin plus collagen, and 4% PS, mimicking platelets stimulated by thrombin. All mutants had at least 10-fold reduced affinities for membranes of 4% PS, and 3 mutants also had decreased apparent affinity for factor X. Monoclonal antibodies against the C2 domain produced different relative impairment of mutants compared with wild-type factor VIII. Monoclonal antibody ESH4 decreased the V(max) for all mutants but only the apparent membrane affinity for wild-type factor VIII. Monoclonal antibody BO2C11 decreased the V(max) of wild-type factor VIII by 90% but decreased the activity of 3 mutants more than 98%. These results identify a membrane-binding face of the factor VIII C1 domain, indicate an influence of the C1 domain on factor VIII binding to factor X, and indicate that cooperation between the C1 and C2 domains is necessary for full activity of the factor Xase complex.

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“…Small unilamellar phospholipid vesicles were prepared by sonication in a bath sonicator (Laboratory Supplies) until the suspension was visually clear. 35 Vesicles were quick frozen in liquid nitrogen and stored at Ϫ80°C. …”

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confidence: 99%

Factor VIII C1 domain residues Lys 2092 and Phe 2093 contribute to membrane binding and cofactor activity

Meems

Meijer

Cullinan

et al. 2009

Blood

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Binding of factor VIII to membranes containing phosphatidyl-L-serine (Ptd-L-Ser) is mediated, in part, by a motif localized to the C2 domain. We evaluated a putative membrane-binding role of the C1 domain using an anti-C1 antibody fragment, KM33 scFv , and factor VIII mutants with an altered KM33 epitope. We prepared a dual mutant Lys2092/Phe2093 3 Ala/ Ala (fVIII YFP 2092/93) and 2 single mutants Lys2092 3 Ala and Phe2093 3 Ala. KM33 scFv inhibited binding of fluorescein-labeled factor VIII to synthetic membranes and inhibited at least 95% of factor Xase activity. fVIII YFP 2092/93 had 3-fold lower affinity for membranes containing 15% Ptd-L-Ser but more than 10-fold reduction in affinity for membranes with 4% Ptd-L-Ser. In a microtiter plate, KM33 scFv was additive with an anti-C2 antibody for blocking binding to vesicles of 15% Ptd-L-Ser, whereas either antibody blocked binding to vesicles of 4% Ptd-L-Ser. KM33 scFv inhibited binding to platelets and fVIII YFP 2092/93 had reduced binding to A23187-stimulated platelets. fVIII YFP 2092 exhibited normal activity at various Ptd-L-Ser concentrations, whereas fVIII YFP 2093 showed a reduction of activity with Ptd-L-Ser less than 12%. fVIII YFP 2092/93 had a greater reduction of activity than either single mutant. These results indicate that Lys 2092 and Phe 2093 are elements of a membrane-binding motif on the factor VIII C1 domain. (Blood. 2009;114:3938-3946) Introduction Factor VIII functions as a cofactor in the membrane-bound intrinsic factor Xase complex. Together with the enzyme factor IXa, activated factor VIII binds to phosphatidyl-L-serine (Ptd-L-Ser)-containing membranes 1,2 to form an enzyme complex that cleaves the zymogen factor X to factor Xa. 3,4 Factor Xa is thereafter responsible for catalyzing prothrombin cleavage to thrombin. 5 The importance of the factor Xase complex is illustrated by the disease hemophilia, in which a deficiency of factor VIII (hemophilia A) or factor IX (hemophilia B) leads to life-threatening bleeding. Despite the central importance of membrane binding, this aspect of factor VIII function remains poorly understood. Factor VIII is synthesized as a single polypeptide chain containing 2351 amino acids (molecular weight, 280 kDa) and shows a domain structure of A1-a1-A2-a2-B-a3-A3-C1-C2, where a1, a2, and a3 are spacer regions that separate the domains from each other. 6 Factor VIII is homologous to factor V in amino acid sequence and domain structure. 7 The A domains are homologous with ceruloplasmin, the C domains with discoidin I, and with lactadherin, 8,9 and the B domain is unique to each protein. 10 The A domains mediate the dominant interactions with factor IXa and factor X in the factor Xase complex, whereas binding to Ptd-L-Ser-containing membranes is mediated predominantly by the C2 domain. 11-15 The structure-function relationships of factor V resemble those of factor VIII in that the A domains mediate the dominant interactions with the enzyme and substrate and the C2 domain mediates the dominant membrane-binding inter...

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Large vesicle contamination in small, unilamellar vesicles

Cited by 68 publications

References 11 publications

Liposomes: Preparation, Characterization, and Preservation

Liposomes: Preparation, Characterization, and Preservation

A membrane-interactive surface on the factor VIII C1 domain cooperates with the C2 domain for cofactor function

Factor VIII C1 domain residues Lys 2092 and Phe 2093 contribute to membrane binding and cofactor activity

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