Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II.
Very low density lipoproteins isolated from guinea pig liver perfusate (VLDLp) lack the equivalent of human apolipoprotein C-II (apoC-II), the activator of lipoprotein lipase (LpL). These lipoproteins are therefore ideal substrates with which to investigate the mechanism by which apoC-II activates t...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
1981-08-01
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| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520373302 |
| _version_ | 1818689017992970240 |
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| author | T J Fitzharris D M Quinn E H Goh J D Johnson M L Kashyap L S Srivastava R L Jackson J A Harmony |
| author_facet | T J Fitzharris D M Quinn E H Goh J D Johnson M L Kashyap L S Srivastava R L Jackson J A Harmony |
| author_sort | T J Fitzharris |
| collection | DOAJ |
| description | Very low density lipoproteins isolated from guinea pig liver perfusate (VLDLp) lack the equivalent of human apolipoprotein C-II (apoC-II), the activator of lipoprotein lipase (LpL). These lipoproteins are therefore ideal substrates with which to investigate the mechanism by which apoC-II activates the enzyme. VLDLp binds apoC-II, and apoC-II associated with VLDLp markedly increases the rate of lipoprotein lipase-catalyzed hydrolysis of VLDLp-triglycerides. The activator potency of apoC-II is independent of the method of enrichment of VLDLp with apoC-II: delipidated human apoC-II and apoC-II transferred from human high density lipoproteins activate lipoprotein lipase to equal extents. ApoC-II causes pH-dependent changes in both apparent Km and VmaX of LpL-catalyzed hydrolysis of VLDLp-triglycerides. At pH l7.4--7.5, the major effects of apoC-II is to decrease the apparent Km by 3.3--4.0 fold. The apparent Vmax is increased 1.3-fold. At pH 6.5 and 8.5, the decrease of apparent Km is less marked, 1.6-fold and 1.4-fold, respectively. At pH 6.5, apoC-II increases the apparent Vmax ty 1.3-fold, while at pH 8.5 the primary effect of apoC-II is a 1.6-fold increase of apparent Vmax. Based on a simple kinetic model, the data suggest that apoC-II favors direct interaction between enzyme and triglyceride within the lipoprotein particle, as well as subsequent catalytic turnover. |
| first_indexed | 2024-12-17T12:03:25Z |
| format | Article |
| id | doaj.art-7e96b9a1132d45f6b3f067256bd48e0b |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-17T12:03:25Z |
| publishDate | 1981-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-7e96b9a1132d45f6b3f067256bd48e0b2022-12-21T21:49:44ZengElsevierJournal of Lipid Research0022-22751981-08-01226921933Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II.T J FitzharrisD M QuinnE H GohJ D JohnsonM L KashyapL S SrivastavaR L JacksonJ A HarmonyVery low density lipoproteins isolated from guinea pig liver perfusate (VLDLp) lack the equivalent of human apolipoprotein C-II (apoC-II), the activator of lipoprotein lipase (LpL). These lipoproteins are therefore ideal substrates with which to investigate the mechanism by which apoC-II activates the enzyme. VLDLp binds apoC-II, and apoC-II associated with VLDLp markedly increases the rate of lipoprotein lipase-catalyzed hydrolysis of VLDLp-triglycerides. The activator potency of apoC-II is independent of the method of enrichment of VLDLp with apoC-II: delipidated human apoC-II and apoC-II transferred from human high density lipoproteins activate lipoprotein lipase to equal extents. ApoC-II causes pH-dependent changes in both apparent Km and VmaX of LpL-catalyzed hydrolysis of VLDLp-triglycerides. At pH l7.4--7.5, the major effects of apoC-II is to decrease the apparent Km by 3.3--4.0 fold. The apparent Vmax is increased 1.3-fold. At pH 6.5 and 8.5, the decrease of apparent Km is less marked, 1.6-fold and 1.4-fold, respectively. At pH 6.5, apoC-II increases the apparent Vmax ty 1.3-fold, while at pH 8.5 the primary effect of apoC-II is a 1.6-fold increase of apparent Vmax. Based on a simple kinetic model, the data suggest that apoC-II favors direct interaction between enzyme and triglyceride within the lipoprotein particle, as well as subsequent catalytic turnover.http://www.sciencedirect.com/science/article/pii/S0022227520373302 |
| spellingShingle | T J Fitzharris D M Quinn E H Goh J D Johnson M L Kashyap L S Srivastava R L Jackson J A Harmony Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II. Journal of Lipid Research |
| title | Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II. |
| title_full | Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II. |
| title_fullStr | Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II. |
| title_full_unstemmed | Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II. |
| title_short | Hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase: activation by hjman apolipoprotein C-II. |
| title_sort | hydrolysis of guinea pig nascent very low density lipoproteins catalyzed by lipoprotein lipase activation by hjman apolipoprotein c ii |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520373302 |
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