Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase
It has previously been shown that when the molecular species specificity of rat liver Golgi CMP-N-acetylneuraminate:lactosylceramide alpha 2,3-sialyltransferase was determined, using as the substrate lactosylceramide (LacCer) incorporated into liposomes prepared with rat liver Golgi lipids, the enzy...
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| Format: | Article |
| Language: | English |
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Elsevier
1993-06-01
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| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520396772 |
| _version_ | 1818647255262953472 |
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| author | H Kadowaki MA Grant LA Williams |
| author_facet | H Kadowaki MA Grant LA Williams |
| author_sort | H Kadowaki |
| collection | DOAJ |
| description | It has previously been shown that when the molecular species specificity of rat liver Golgi CMP-N-acetylneuraminate:lactosylceramide alpha 2,3-sialyltransferase was determined, using as the substrate lactosylceramide (LacCer) incorporated into liposomes prepared with rat liver Golgi lipids, the enzyme showed a pronounced variation in activity towards the various molecular species of LacCer (J. Lipid Res. 1989. 30: 1789-1797). In this paper, -the LacCer molecular species specificity of sialyltransferase from neuroblastoma NB2a cells was examined using five naturally occurring and three synthetic molecular species of LacCer. The enzyme activity was determined by following the formation of [14C]GM3 from CMP-[14C]neuraminic acid and individual molecular species of LacCer incorporated into liposomes. Nonspecific lipid transfer protein was included in the enzyme assay to facilitate the transfer of LacCer and other lipids between the liposomes and the membrane where sialyltransferase is located. In these enzyme assays the liposomes contained approximately 10 times more lipid phosphorus than either the microsomal fraction of NB2a cells or the Golgi fraction of rat liver. Thus, in the presence of nonspecific lipid transfer protein, the lipid composition of the membrane where sialyltransferase is located was modified to resemble the lipid composition of the liposomes. When the molecular species specificity of NB2a cell sialyltransferase was determined with LacCer incorporated into liposomes prepared with NB2a cell lipids, the enzyme showed no specificity towards the various molecular species of LacCer. However, when the molecular species specificity of NB2a cell sialyltransferase was determined with LacCer incorporated into liposomes prepared with rat liver Golgi lipids, the enzyme showed a variation in activity towards the various LacCer molecular species similar to that observed with the liver Golgi enzyme using liposomes prepared with liver Golgi lipids. Likewise, when the molecular species specificity of rat liver Golgi sialyltransferase was determined with LacCer incorporated into liposomes prepared with NB2a cell lipids, the liver enzyme then showed no specificity towards the various molecular species of LacCer. These results indicate that the lipid environment of the membrane can alter the molecular species specificity of sialyltransferase towards its lipid substrate, LacCer. |
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| format | Article |
| id | doaj.art-e813d9db568c457cbecc6aee8a5d7c98 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-17T00:59:37Z |
| publishDate | 1993-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-e813d9db568c457cbecc6aee8a5d7c982022-12-21T22:09:31ZengElsevierJournal of Lipid Research0022-22751993-06-01346905914Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferaseH Kadowaki0MA Grant1LA Williams2Department of Medicine, Boston University School of Medicine, Boston, MA 02118.Department of Medicine, Boston University School of Medicine, Boston, MA 02118.Department of Medicine, Boston University School of Medicine, Boston, MA 02118.It has previously been shown that when the molecular species specificity of rat liver Golgi CMP-N-acetylneuraminate:lactosylceramide alpha 2,3-sialyltransferase was determined, using as the substrate lactosylceramide (LacCer) incorporated into liposomes prepared with rat liver Golgi lipids, the enzyme showed a pronounced variation in activity towards the various molecular species of LacCer (J. Lipid Res. 1989. 30: 1789-1797). In this paper, -the LacCer molecular species specificity of sialyltransferase from neuroblastoma NB2a cells was examined using five naturally occurring and three synthetic molecular species of LacCer. The enzyme activity was determined by following the formation of [14C]GM3 from CMP-[14C]neuraminic acid and individual molecular species of LacCer incorporated into liposomes. Nonspecific lipid transfer protein was included in the enzyme assay to facilitate the transfer of LacCer and other lipids between the liposomes and the membrane where sialyltransferase is located. In these enzyme assays the liposomes contained approximately 10 times more lipid phosphorus than either the microsomal fraction of NB2a cells or the Golgi fraction of rat liver. Thus, in the presence of nonspecific lipid transfer protein, the lipid composition of the membrane where sialyltransferase is located was modified to resemble the lipid composition of the liposomes. When the molecular species specificity of NB2a cell sialyltransferase was determined with LacCer incorporated into liposomes prepared with NB2a cell lipids, the enzyme showed no specificity towards the various molecular species of LacCer. However, when the molecular species specificity of NB2a cell sialyltransferase was determined with LacCer incorporated into liposomes prepared with rat liver Golgi lipids, the enzyme showed a variation in activity towards the various LacCer molecular species similar to that observed with the liver Golgi enzyme using liposomes prepared with liver Golgi lipids. Likewise, when the molecular species specificity of rat liver Golgi sialyltransferase was determined with LacCer incorporated into liposomes prepared with NB2a cell lipids, the liver enzyme then showed no specificity towards the various molecular species of LacCer. These results indicate that the lipid environment of the membrane can alter the molecular species specificity of sialyltransferase towards its lipid substrate, LacCer.http://www.sciencedirect.com/science/article/pii/S0022227520396772 |
| spellingShingle | H Kadowaki MA Grant LA Williams Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase Journal of Lipid Research |
| title | Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase |
| title_full | Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase |
| title_fullStr | Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase |
| title_full_unstemmed | Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase |
| title_short | Effect of membrane lipids on the lactosylceramide molecular species specificity of CMP-N-acetylneuraminate:lactosylceramide sialyltransferase |
| title_sort | effect of membrane lipids on the lactosylceramide molecular species specificity of cmp n acetylneuraminate lactosylceramide sialyltransferase |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520396772 |
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