title: Covalent cross-linking of photosensitive phospholipids to human serum high density apolipoproteins (apoHDL).
abstract: Human serum high density apolipoproteins were reassociated with three different lecithin species substituted with radioactively labelled photosensitive azido fatty acids, bis([3H]-16-azidopalmitoyl)-, bis([3H]12-azidooleoyl)- and bis([3H]18-azidolinoleoyl)glycerophosphocholine. The lipoprotein particles were reconstituted from a mixture of azido-labelled phosphatidylcholine and non-labelled dioleoylglycerophosphocholine (1:9). Excess lipid was separated from the homogeneous particles by Bio-Gel A-5m. The molecular weight, stoichiometry, fluorescence and circular dichroism of the reconstituted particles were determined before and after photoactivation with covalent cross-linking of the phospholipids with the apoproteins. The physical parameters of the reconstituted lipoproteins remained unperturbed by the cross-linking reaction between the generated nitrenes and apolipoprotein A-I and A-II. Thus the hydrophobic interactions of the phospholipid molecules with the apoproteins have been proved for the first time by a chemical method.
mesh_terms: D001053:Apolipoproteins / Q000097:blood; D001386:Azides; D002942:Circular Dichroism; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood; D010713:Phosphatidylcholines; D010743:Phospholipids / Q000097:blood; D010777:Photochemistry; D011485:Protein Binding; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001053:Apolipoproteins; D001386:Azides; D008075:Lipoproteins, HDL; D010713:Phosphatidylcholines; D010743:Phospholipids