Abstract
In this disorder (NA), normal plasma low density lipoproteins (LDL) are absent but intestinal absorption of fat is normal. Levels of spherical, triglyceride-rich lipoproteins, 300 to 1000 Å in diameter, rise markedly in plasma during fat absorption. Though 40% of their protein is insoluble in 4.2M tetramethylurea, it has only limited immunoreactivity with antibodies to apo B of LDL. Its apparent molecular weight (MWapp) in SDS is identical to that of the B-48 protein of normal human chylomicrons and it has a similar amino acid composition. The B-100 protein found in normal very low density lipoproteins and LDL, which has a much larger MWapp, is undetectable. This suggests that the B-48 and B-100 proteins are under separate genetic control and that NA results from selective deletion of the B-100 apolipoprotein. We purified chylomicrons from serum of a patient with NA, labeled them with 131I, reinfused them and isolated B-48 protein from serum lipoproteins by SDS gel electrophoresis. The label disappeared with a t1/2 of 52 minutes. Minimal labeling was detected briefly in lipoproteins of intermediate density (12% of total 131I at 2 minutes, none thereafter) and none in the LDL interval. We conclude that the B-100 apolipoprotein is required for formation of LDL and that the B-48 apoprotein of chylomicrons is not converted to apo B of LDL.
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Malloy, M., Kane, J. & Piel, C. 1155 NORMOTRIGLYCERIDEMIC ABETALIPOPROTEINEMIA: FATE OF APOLIPOPROTEIN B OF CHYLOMICRONS. Pediatr Res 15 (Suppl 4), 635 (1981). https://doi.org/10.1203/00006450-198104001-01181
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DOI: https://doi.org/10.1203/00006450-198104001-01181