Presence of covalently attached fatty acids in rat apolipoprotein B via thiolester linkages.
Thiolester linked lipids in rat apolipoprotein B (ApoB) were examined by incubating reduced and carboxymethylated ApoB in 6 M urea buffer with [14C]methylamine at pH 8.5, 30 degrees C. It was observed that [14C]methylamine was covalently incorporated into ApoB, and there was a [14C]methylamine modified product which was lipid in nature. After extraction with organic solvents, the [14C]methylamine labeled product showed its Rf on TLC to be similar to that of the synthetic N-methyl fatty acyl amide. After purification on TLC and transesterification with 3 N methanolic HC1, methyl esters of C16:0, C18:0 and C18:1 fatty acids were identified by gas-liquid chromatography. These results suggest that rat ApoB, similar to human ApoB, contained covalently linked fatty acids through the high energy, labile thiolester bonds.
Kamanna
V S
VS
Lipoprotein and Atherosclerosis Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104.
Lee
D M
DM
D000818:Animals; D001055:Apolipoproteins B / Q000378:metabolism*; D002845:Chromatography; D002855:Chromatography, Thin Layer; D004952:Esters; D005227:Fatty Acids / Q000378:metabolism*; D051381:Rats; D013438:Sulfhydryl Compounds
D001055:Apolipoproteins B; D004952:Esters; D005227:Fatty Acids; D013438:Sulfhydryl Compounds