Role of Apolipoprotein A IV in the Interconversion of HDL Subclasses
Apolipoprotein A-IV (apo A-IV) is a protein of molecular weight 46 000, present in lymph and plasma chylomicrons, very low density lipoproteins (VLDL) and high density lipoproteins (HDL) in various species including man (1, 2) and is presently considered as a real apolipoprotein. However, unlike most apolipoproteins, apo A-IV has a low affinity for plasma lipoproteins (3-5). It is a relatively hydrophilic protein with the weakest lipid affinity of any human apolipoprotein (6). It is marginally stable in aqueous solution compared to other apolipoproteins and its lipid binding properties are highly sensitive to the environment (5). It presents high self-association tendancies, mainly as dimer associations. All these special properties could be explained by the structural characteristics of the molecule which presents an association of a highly alpha-helical structure (35-54%) (5, 7) and a strongly hydrophobic domain.
KeywordsHigh Density Lipoprotein High Density Lipoprotein Reverse Cholesterol Transport Lipoprotein Fraction Cholesterol Acyl Transferase
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