Activation of lipoprotein lipase by apolipoprotein C-II is modulated by the COOH terminal region of apolipoprotein C-III
✍ Scribed by Alberico L. Catapano
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 450 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0009-3084
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✦ Synopsis
The in vitro effect of apofipeprotein C-II (ape C-II) on the apofipoprotein C-HI (ape C-III) induced activation of bovine milk lipeprotein fipase (LPL) was studied in vitro using a synthetic substrate. Ape C-III effectively inlu'bited, in a dose-dependent manner, the activation of lipoprotein lipase induced by ape C-II. A 3-fold molar ape C-III excess decreased the lipoprotein lipase activity by 25%. Thrombin cleavage of ape C4II produced two fragments: only fragment 41-79 retained the inh~Jtory activity and was equipotent to native ape C-III 1 on a molar basis. Neither displacement of ape C-II from the substrate, as determined using l~sI-labeled ape C-II, nor the charge carded by sialic residues of ape C-HI, as demonstrated in experiments performed after neuraminidase treatment, accounted for this effect. I speculate that apo C-IIl may act by inhibiting the ape C-II-LPL interaction.