Conformational changes and physicochemical properties of transferrin upon derivatization with cholesterol

✍ Scribed by E. Ardite; M.A. Egea; I. Haro; F. Reig; M.A. Alsina

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 883 KB
• Volume: 290
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(94)80042-1

✦ Synopsis

Abstraet

Transferrin was chemically modified by covalent linkage of cholestetyloxycarbonyl-6-aminohexanoic acid to the lysine amino groups. Cholesteryloxycarbonyl-6aminohexanoic acid was prepared from cholestetyl chlorocarbonate and 6aminohexanoic acid. This derivative was attached by an amide bond to the free amino groups of transferrin. The level of derivatixation was quantitated by amino acid analysis and determination of free amino groups by the trinitrobenxene sulfonic acid method. The physicochemical characteristics of native and derivatized transferrin were studied by several methods. Surface activity was determined by the pressure increases at the air/water interface. Surface hydrophobicity was checked by aniline naphthalene sulfonic acid titration. Lipid-protein interactions were determined by intrinsic fluorescence changes, with the bilayers in the fluid and gel state. The results obtained show that derivatixation renders the protein highly hydrophobic. Nevertheless, the surface activity or the interaction with lipids do not correlate with the hydrophobicity of the molecule, thus suggesting the formation of some type of internal micelles or a strongly packed structure.