Apoprotein composition of very low density lipoproteins of human serum.

Kane, John P.; Sata, Teizo; Hamilton, Robert L.; Havel, Richard J.

doi:10.1172/jci108245

Cited by 369 publications

(111 citation statements)

References 23 publications

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“…Nearby all of the lightest VLDL particles contained apo C-lll (85%) and, as expected from the literature, 29 -36^ the relative number of lipoproteins that contain apo C-lll fell progressively from VLDL, to LDL 2 (Table 4); but it is important to note that about 25% of the LDL 2 particles contained at least one molecule of apo C-lll. Similar observations were made with apo C-l and apo D; the proportions of lipoproteins containing these apolipoproteins also decreased with increasing lipoprotein density, but again a highly significant proportion of the LDL 2 particles still contained these two apolipoproteins.…”

Section: Association Of Other Apolipoproteins With Apolipoprotein B-csupporting

confidence: 78%

Expression of apolipoprotein B epitopes in lipoproteins. Relationship to conformation and function.

Marcel¹,

Hogue²,

Weech³

et al. 1988

Arteriosclerosis

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The immunochemical properties of apolipoprotein (apo) B have been studied in very low density lipoprotein (VLDL), (Sf 100 to 400), VLDL 2 (Sf 60 to 100), VLDL 3 (Sf20 to 60), different intermediate density lipoprotein (IDL), and low density lipoprotein (LDL) subfractions isolated from patients with type IV hypertriglyceridemia. In these lipoproteins, we characterized the association of apo B with other apolipoproteins and the expression and immunoreactivity of several apo B epitopes close to the apo B receptor binding sites (3F5, 4G3, 3A8, and 5E11) and of other epitopes located on the apo B100-B48 common region (1D1 and 2D8). Immunoprecipitation showed that the proportion of lipoprotein particles expressing each apo B epitope increased from VLDL, to LDL*; this was more apparent with 3A8 and SE11 than with 3F5. The VLDL that were negative for apo E epitopes (60% or more of the total) were enriched in apo C. The lipoprotein particles containing apo E and/or apo C-lll decreased progressively from VLDL, (30% and 85%, respectively) to LDL 2 (10% and 25%, respectively). Similar observations were made for apo C-l and apo D, demonstrating that apolipoprotein heterogeneity is greatest in the lightest lipoproteins. By competitive radioimmunoassay, the epitope for 4G3 was equally immunoreactive in each lipoprotein subclass, and the affinity constant (Ka) of 4G3 for different lipoproteins showed little variation. In contrast, both immunoreactivity and Ka of 3A8 and 5E11 increased progressively and significantly with the increasing density of the lipoprotein subclasses. This phenomenon is correlated with the increasing binding affinity of apo B in these lipoprotein subclasses to the LDL receptor of fibroblasts. We conclude that, as the apo B-containing lipoproteins become smaller, the conformation of specific regions of apo B is modified: in the receptor binding domain, the conformation of epitope 4G3, which is mapped between residues 2980 and 3080, remains constant, while that of 3A8 and 5E11 (residues 3441 to 3568) changes progressively. We propose the theory that the change in conformation in the domain spanning residues 3441 and 3568 allows the maximum expression of epitopes 3A8 and 5E11 and of the receptor binding site. 23 The size and density heterogeneity of the apo B-containing lipoproteins appear to be introduced not only at the time of secretion of nascent lipoproteins 4 but also during catabolism, 5 the end-point of which is the cellular uptake via receptors that recognize either apo B-100 or apo E or both. 6 In the course of the intravascular transformation of VLDL, the ligand responsible for the binding of the lipo- Received March 31, 1988; revision accepted June 24, 1988. protein to the apo B/E receptor changes progressively from apo E to apo B as the particle becomes smaller, 78 and this transformation is most pronounced at the stage of VLDL 3 (Sf 20 to 60). The studies of Gianturco et al. 7 and Bradley et al. 9 have shown that the apo E-mediated affinity of the VLDL for the apo B/E receptor is depen...

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Section: Association Of Other Apolipoproteins With Apolipoprotein B-csupporting

confidence: 78%

Expression of apolipoprotein B epitopes in lipoproteins. Relationship to conformation and function.

Marcel¹,

Hogue²,

Weech³

et al. 1988

Arteriosclerosis

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“…27 Protein was measured by the Lowry technique with correction for hydration of the albumin standard. 28 Electron microscopy of lipoprotein fractions was performed on samples negatively stained with potassium phosphotungstate. 29 Particle diameters were measured on the photographic negative plates with a Nikon optical microcomparator (Model 6 C, Nippon Kogaku, KK, Tokyo, Japan).…”

Section: Lipoprotein Analysesmentioning

confidence: 99%

Remnants of lipoproteins of intestinal and hepatic origin in familial dysbetalipoproteinemia.

Kane¹,

Chen²,

Hamilton³

et al. 1983

Arteriosclerosis

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102

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We used the low molecular weight form of apolipoprotein B (B-48) as a marker for the identification of remnant particles formed from chyiomicrons in the plasma of patients with familial dysbetalipoproteinemia. In the serum of patients fasted 14 hours, the d < 1.006 g/cm 3 lipoproteins of prebeta mobility, separated by starch block electrophoresis, contained only the primary hepatogenous species of apolipoprotein B (B-100), and their llpld composition resembled that of normal prebeta very low density lipoproteins. In contrast, the fraction with beta mobility contained both the B-48 and B-100 proteins; the B-48 protein was found primarily among the largest particles. All fractions of beta mobility were greatly enriched with choiesteryi esters. The beta fraction thus contains remnant particles which appear to originate both from chyiomicrons and hepatogenous very low density lipoproteins. It appears that these remnant particles share a common removal mechanism which is impaired in familial dysbetalipoproteinemia. (Arteriosclerosis 3:47-56, January/February 1983) amilial dysbetalipoproteinemia (F. dys.) (type III hyperlipoproteinemia) is now recognized as a disorder in which remnant-like particles, formed from triglyceride-rich lipoproteins, accumulate in plasma.12 Clinically, it is associated with arteriosclerosis of both the coronary and peripheral circulations. 3These remnant-like lipoprotein particles are enriched with choiesteryi esters 1 2 ' 4 and have beta mobility upon electrophoresis in agarose gel, in contrast with normal very low density lipoproteins (VLDL), which have prebeta mobility. The electrophoretic mobility of remnant particles is accounted for principally by deficiency of the C-apoproteins, which are normally the preponderant species in VLDL, with retention of appreciable quantities of less anionic apolipoprotein E (apo E). 5 The initial stages of intravascular lipolysis appear to proceed relatively normally. Removal of remnant particles from the plasma normally occurs rapidly by means of receptor-mediated endocytosis in the liver.2 In F. dys., however, there is

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“…Sniderman and associates 23 made an important contribution with the recognition that some patients have high concentrations of apo B in the presence of "normal" serum cholesterol levels. Without question, low density lipoprotein (LDL) apo B levels can be disproportionately high compared to cholesterol levels.…”

mentioning

confidence: 99%

“…The immunological methods currently available for apo B are radial immunodiffusion, 23 radioimmunoassay, 16 electroimmunoassay, 1718 enzyme-linked immunosorbent assay, 19 and nephetometric immunoassay. 20 Opinion differs as to which of these approaches is preferable.…”

mentioning

confidence: 99%