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Start Over Author "Hammarström, S." Journal journal of lipid research
6 results on '"Hammarström, S."'

2. Identification of subunits of the 650 kDa 12(S)-HETE binding complex in carcinoma cells.

Author

Herbertsson, H, Kühme, T, Evertsson, U, Wigren, J, and Hammarström, S

Abstract

Cytosol and nuclei of Lewis lung carcinoma (LLC) cells contain high affinity binding sites specific for the arachidonic acid metabolite 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid (12(S)-HETE). In this report we present evidence that the cytosolic 12(S)-HETE binding complex also occurs in human erythroleukemia (HEL) and promonocytic leukemia (U937) cells as well as in murine 3T3-L1 preadipocytes but not in intestinal epithelial cells (Int407). The cytosolic 650 kDa 12(S)-HETE-binding complex was found to consist of subunits; raising the ATP concentration in cytosol led to conversion of the 650 kDa complex to a 50 kDa binding component, presumably the actual 12(S)-HETE binding polypeptide. Lowering of the cytosolic concentration of ATP had the opposite effect, i.e., the amount of the 650 kDa complex increased. Another subunit of the 650 kDa complex was identified as heat shock protein 70 (hsp70) by Western blot analyses and coimmunoprecipitation. Hsp70 was present in substoichiometric amounts, in an approximate 1:6 ratio. The multimeric nature of the binding complex and the identification of hsp70 as a subunit suggest that there are similarities between the 12(S)-HETE binding protein and receptors of the steroid/thyroid hormone superfamily.

Published
1998

3. Gas–liquid chromatography–mass spectrometry of synthetic ceramides containing 2-hydroxy acids

Author

Hammarström, S., Samuelsson, B., and Samuelsson, K.

Abstract

Ceramides containing either sphingosine or sphinganine and one of the 2-hydroxy acids, 14h:0, 16h:0, 18h:0, 20h:0, 22h:0, 24h:0, and 26h:0 were prepared and separated by gas chromatography as the 1,3,2'-tri-O-tri-methylsilyl derivatives. Mass spectrometric analyses of these derivatives showed that the ions formed on electron impact can be used to determine unequivocally the structures of the long-chain base and the fatty acid residue in the ceramide. Proposed structures of ions and the mechanisms of reaction of their formation are supported by mass spectra of homologous derivatives, by deuterium labeling experiments, and by high-resolution on mass spectrometry.

Published
1970
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4. Identification and quantitation of free ceramides in human platelets.

Author

Krivit W and Hammarström S

Subjects
Blood Proteins analysis, Carbon Isotopes, Ceramides analysis, Ceramides blood, Chromatography, Chromatography, Gas, Chromatography, Thin Layer, Fatty Acids analysis, Humans, Lipids analysis, Mass Spectrometry, Palmitic Acids analysis, Sphingosine analysis, Stearic Acids analysis, Blood Platelets analysis, Ceramides isolation & purification
Abstract

Free ceramides were isolated from human platelets. Their structures were unequivocally determined by gas-liquid chromatography-mass spectrometry of the trimethylsilyl ether derivatives. The major components were N-(palmitoyl) sphingosine, N-(stearoyl) sphingosine, N-(eicosanoyl) sphingosine, N-(docosanoyl) sphingosine, N-(tetracosanoyl) sphingosine, and N-(tetracosenoyl) sphingosine. Sphinganine-and sphingadienine-containing ceramides as well as ceramides containing other unsaturated acids were also present. The amount of ceramides was determined by quantitative gas-liquid chromatography, using radioactive ceramide as internal standard and synthetic crystalline ceramides for comparison of peak areas. The concentration of ceramides was found to be 1.31 micro g/10(9) platelets or 0.47 micro g/mg of platelet protein.

Published
1972

5. Gas-liquid chromatography-mass spectrometry of synthetic ceramides containing phytosphingosine.

Author

Hammarström S

Subjects
Chromatography, Gas, Deuterium, Spectrum Analysis, Amino Alcohols analysis, Amino Alcohols chemical synthesis, Fatty Acids analysis, Glycols analysis, Glycols chemical synthesis
Abstract

Ceramides containing phytosphingosine as base and one of the fatty acids 16:0, 18:0, 20:0, 22:0, 23:0, and 24:0, were prepared by direct coupling in the presence of a mixed carbodiimide. The ceramides were analyzed as the 1,3,4-tri-O-trimethylsilyl ether derivatives by gas-liquid chromatography-mass spectrometry. Gas chromatographic data is presented, and structures of mass spectral ions are suggested. The structures are supported by mass spectra of the homologous ceramides, by deuterium-labeling experiments, and by high resolution mass spectrometry. Some ions, formed by cleavage between C-3 and C-4 in the long-chain base, indicate the phytosphingosine nature of the ceramide.

Published
1970

6. A convenient procedure for the synthesis of ceramides.

Author

Hammarström S

Subjects
Acylation, Chromatography, Gas, Chromatography, Thin Layer, Fatty Acids, Infrared Rays, Mass Spectrometry, Optical Rotation, Spectrum Analysis, Sphingolipids, Stereoisomerism, Ceramides chemical synthesis
Abstract

A procedure for the preparation of ceramides by direct coupling of long-chain bases and fatty acids in the presence of a mixed carbodiimide is described. This method has been used to prepare ceramides containing sphing-4-enine or sphinganine and various saturated and unsaturated fatty acids as well as saturated 2-hydroxy acids. Ceramides containing 4-hydroxy sphinganine and saturated nonhydroxy acids have also been prepared. The yields were 60-75%. The characterization of these compounds by gas-liquid chromatography-mass spectrometry as trimethylsilyl derivatives has been previously reported. Some of the ceramides are further characterized in this report by infrared spectroscopy and one compound, in addition, by elementary analysis. Use of racemic constituents for 2-hydroxy acid ceramide syntheses leads to the formation of diastereoisomers which separate by thin-layer chromatography. These were characterized by gas-liquid chromatography-mass spectrometry as the trimethylsilyl derivatives and by infrared spectroscopy. Their configurations were established by syntheses with optically active constituents.

Published
1971

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