Microcalorimetric study of phospholipid binding to human apo-HDL

✍ Scribed by M.Y. Rosseneu; F. Soetewey; V. Blaton; J. Lievens; H. Peeters

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 528 KB
• Volume: 13
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(74)90020-6

✦ Synopsis

The binding of lysolecithin and synthetic short-chain lecithins: di-caproyl, di-lauroyl and dimyristoyl lecithins to a human apo-high density lipoprotein (apo-HDL) was followed by microcalorimetry. Complex formation was checked by ultracentrifugal flotation.

The binding reaction was very rapid and strongly exothermal. The apparent binding enthalpy AH B together with the complex composition were computed from the binding curves. Both quantities were of the same order of magnitude for lysolecithin and for the shorter chain lecithins while the binding of di-myristoyl lecithin was characterized by a more highly exotherreal reaction.

The structure of the lipid phase strongly influences the enthalpy change. In the case of lysolecithin and of the shorter chain lecithins; which form micellar structures in water, the enthalpy change is mainly due to apoprotein-phospholipid complex formation.

The disrupture of the myelin figures formed by the di-myristoyl lecithin accounts for the complementary heat effect.

The phospholipid composition of the complexes isolated by ultracentrifugal flotation was lower than that determined by microcalorimetry, due to the presence of high salt concentrations in the ultracentrifuge.