scholarly journals Polypeptides From Serum Low-Density Lipoproteins of Pigs (Sus Domesticus)

1976 ◽  
Vol 29 (4) ◽  
pp. 301
Author(s):  
CS Walkley ◽  
DR Husbands
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Soluble Protein ◽  
Analytical Ultracentrifugation ◽  
Apparent Molecular Weight ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Protein Chromatography ◽  
The Third ◽  
Sus Domesticus

Low-density lipoproteins floating between densities 1� 006 and 1 . 063 g cm - 3 were isolated by centrifugation of blood serum obtained from 24-h fasted pigs (Sus domesticus). This lipoprotein fraction contained two components with SF 1 . 063 values of 3 . 4 and 2� 3 at 20DC when examined by analytical ultracentrifugation. Delipidation of the lipoprotein yielded 15 % recovery of soluble protein whereas succinylation of the lipoprotein prior to delipidation gave 95 % recovery of soluble protein. Chromatography on Sephadex Gl00 in 8 M urea of these delipidation products yielded three fractions of different sizes which were present in both native and succinylated apoproteins. These fractions from the succinylated apolipoproteins were further characterized. A polypeptide fraction comprising 70 % of the total protein had an apparent molecular weight of 34000 and contained greater amounts of amino acids with hydrophobic side chains than did the second fraction of apparent molecular weight 22000 which contained 15 % of the protein. The third fraction of apparent molecular weight 12 500 contained 15 % of the protein.

The major glycoprotein in germinating bean seeds

1971 ◽  
Vol 49 (12) ◽  
pp. 2107-2111 ◽  
Author(s):  
David Racusen ◽  
Murray Foote
Keyword(s):  
Molecular Weight ◽  
Phaseolus Vulgaris ◽  
Total Protein ◽  
Soluble Protein ◽  
Deae Cellulose ◽  
Apparent Molecular Weight ◽  
Disc Electrophoresis ◽  
Total Soluble Protein ◽  
Combined Analysis

Bean seeds (Phaseolus vulgaris) yielded a soluble glycoprotein that accounted for about 35% of the total protein as determined by combined analysis with DEAE-cellulose and disc electrophoresis. Germination for up to 114 h had little effect on this glycoprotein or on the total soluble protein. The glycoprotein had an apparent molecular weight of 130 000 (6.1 S), contained 14.7% nitrogen, and yielded mannose, glucosamine, and some pentose upon hydrolysis.

Processing and characterization of the low density lipoprotein receptor in the human colonic carcinoma cell subclone HT29-18: A potential pathway for delivering therapeutic drugs and genes

1992 ◽  
Vol 12 (6) ◽  
pp. 483-494 ◽  
Author(s):  
J. C. Mazière ◽  
C. Mazière ◽  
S. Emami ◽  
B. Noel ◽  
Y. Poumay ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carcinoma Cell ◽  
Low Density Lipoprotein ◽  
Human Fibroblasts ◽  
Density Lipoprotein ◽  
Apparent Molecular Weight ◽  
Colonic Carcinoma ◽  
Sterol Synthesis ◽  
Low Density ◽  
Ldl Binding

Low density lipoprotein (LDL) processing has been investigated in the subcloned human colonic carcinoma cell line HT29-18. LDL binding at 4°C was a saturable process in relation to time and LDL concentration. The Kd for LDL binding was 11 μg/ml. ApoE-free HDL3 or acetylated LDL did not significantly compete with125I-LDL binding, up to 500 μg/ml.125I-LDL binding was decreased by 70% in HT29-18 cells preincubated for 24 hours in culture medium containing 100 μg/ml unlabelled LDL. Ligand blotting studies performed on HT29-18 homogenates using colloidal gold labelled LDL indicated the presence of one autoradiographic band corresponding to an apparent molecular weight of 130 kDa, which is consistent with the previously reported molecular weight of the LDL receptor in human fibroblasts. At 37°C,125I-LDL was actively internalized by HT29-18 cells and lysosomal degradation occurred as demonstrated by the inhibitory effect of chloroquine. LDL uptake and degradation by HT29-18 cells also resulted in a marked decrease in endogenous sterol synthesis. These data demonstrate that the HT29-18 human cancerous intestinal cells are able to specifically bind and internalize LDL, and that LDL processing results in down-regulation of sterol biosynthesis. Thus, intestinal epithelial cells possess specific LDL receptors that can be exploited to accomplish drug delivery and gene transfer via the receptor-mediated endocytosis pathway.

Secretion of nascent lipoproteins by isolated rat hepatocytes

1981 ◽  
Vol 59 (8) ◽  
pp. 676-686 ◽  
Author(s):  
Elaine S. Krul ◽  
Peter J. Dolphin ◽  
David Rubinstein
Keyword(s):  
Molecular Weight ◽  
Rat Hepatocytes ◽  
Low Density Lipoproteins ◽  
Cell Protein ◽  
Low Density ◽  
Isolated Rat Hepatocytes ◽  
Apo B ◽  
G Cell ◽  
Apo E ◽  
Isolated Rat

The nature of the nascent lipoproteins secreted by suspensions of isolated rat hepatocytes incubated in a lipid-deficient medium was investigated. Samples of the concentrated medium after 12 and 24 h of incubation were resolved by gel filtration and demonstrated that lipoproteins were secreted with a wide spectrum of particle sizes. Particles corresponding to sizes of serum very low density lipoproteins (VLDL) and low density lipoproteins (LDL) had similar levels of apolipoproteins (apo) B and E as serum VLDL when determined by electroimmunoassay, suggesting that the liver cell secretes a "small" VLDL under these conditions and not an LDL particle as present in the serum. Lipid analyses of the secreted triglyceride-rich particles show them to be similar in composition to serum VLDL with the exception of their cholesterol ester content, which was much lower in the hepatocyte-secreted VLDL. Incorporation of 3H-labelled amino acids into the VLDL apoproteins from the incubation medium after 24 h was determined after ultracentrifugal isolation (d < 1.063 g∙mL−1) and urea–gel electrophoresis, and found to be 70% and 22% of the total applied radioactivity for apo B and apo E, respectively. The lack of immunochemicaily detectable apo C-II and C-III in the isolated nascent VLDL and the lack of significant radioactive incorporation confirmed their visual absence from the gels. Further purification of the VLDL apo E by immunoaffinity chromatography showed it to consist of two narrowly separated bands on 7 M urea – polyacrylamide gels. Apo B was secreted only with particles having mean diameters of greater than 194 Å. In contrast, 75% of the total secreted apo E was associated with fractions of smaller particle diameters. This apo E (LpE) was almost equally distributed in two peaks corresponding to a particle size of approximately 100 Å and a molecular weight of < 60 000, respectively. Only 35% of the total apo E was found in the comparable fractions when hepatocytes from hypercholesterolemic rats were used. Thus, normal hepatocytes secrete a significant proportion of apo E, as a low molecular weight, essentially lipid-free form. The apparent secretion rates, for the apoproteins (mean ± SEM) for hepatocytes from normal rats, were 77.0 + 10.6 μg∙h−1∙g cell protein−1 (apo B) and 71.7 ± 8.6 μg∙h−1∙g cell protein−1 (apo E) after 24 h.

Loss of A-Apoprotein Immunoreactivity during High-Density Lipoprotein Separation

1981 ◽  
Vol 18 (5) ◽  
pp. 308-313 ◽  
Author(s):  
P Johnson ◽  
R A Muirhead ◽  
T Deegan
Keyword(s):  
High Density Lipoprotein ◽  
Surface Structure ◽  
Analytical Ultracentrifugation ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density Lipoproteins ◽  
High Density ◽  
Low Density ◽  
Apoprotein B

By use of an electroimmunoassay, concentrations of A-apoproteins were estimated in serum and in corresponding apoprotein fractions isolated by ultracentrifugation. These values were compared with high-density lipoprotein concentrations determined by analytical ultracentrifugation. Concentrations of A-apoproteins estimated in serum were considerably higher than in isolated high-density lipoprotein fractions. These discrepancies could not be accounted for entirely by material losses into other fractions during ultracentrifugal fractionation. No comparable differences in apoprotein-B concentrations were observed during the ultracentrifugal separation of low-density lipoprotein. Concentrations of A-apoproteins estimated in the residual serum after precipitation of low-density lipoproteins by heparin and manganous ions were also lower than in the corresponding whole sera. The discrepancies persisted after treatment of serum and isolated fractions with tetramethylurea, urea (9 mol/l), and by heating at 52°C for 3 hours. It is considered that separation by ultracentrifugation induces subtle alterations in the surface structure of the lipoprotein species which give rise to changes in immunoreactivity.

Molecular weight distributions of polydisperse systems: application to very low density lipoproteins

Biochemistry ◽  
1978 ◽  
Vol 17 (10) ◽  
pp. 1936-1942 ◽  
Author(s):  
Steven T. Kunitake ◽  
Eugene Loh ◽  
Verne N. Schumaker ◽  
Shun Kin Ma ◽  
Charles M. Knobler ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Very Low Density Lipoproteins ◽  
Molecular Weight Distributions ◽  
Weight Distributions

scholarly journals Extension of resolution and oligomerization-state studies of 2,4′-dihydroxyacetophenone dioxygenase fromAlcaligenessp. 4HAP

2015 ◽  
Vol 71 (10) ◽  
pp. 1258-1263 ◽  
Author(s):  
J. Guo ◽  
P. Erskine ◽  
A. R. Coker ◽  
J. Gor ◽  
S. J. Perkins ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Molecular Weight ◽  
Formic Acid ◽  
Analytical Ultracentrifugation ◽  
Ralstonia Eutropha ◽  
Gel Filtration ◽  
Apparent Molecular Weight ◽  
Structural Basis ◽  
Hydroxybenzoic Acid ◽  
Tetrameric Structure

The enzyme 2,4′-dihydroxyacetophenone dioxygenase (DAD) catalyses the conversion of 2,4′-dihydroxyacetophenone to 4-hydroxybenzoic acid and formic acid. This enzyme is a very unusual dioxygenase in that it cleaves a C—C bond in a substituent of the aromatic ring rather than within the ring itself. Whilst it has been shown that DAD is a tetramer in solution, the recently solved crystal structure of theAlcaligenessp. 4HAP enzyme was in fact dimeric rather than tetrameric. Since the use of limited chymotrypsinolysis, which apparently results in removal of the first 20 or so N-terminal residues of DAD, was necessary for crystallization of the protein, it was investigated whether this was responsible for the change in its oligomerization state. Gel-filtration and analytical ultracentrifugation studies were conducted, which confirmed that chymotrypsinolysed DAD has an apparent molecular weight of around 40 kDa, corresponding to a dimer. In contrast, the native enzyme has a molecular weight in the 70–80 kDa region, as expected for the tetramer. The structural basis for tetramerization has been investigated by the use of several docking servers, and the results are remarkably consistent with the tetrameric structure of a homologous cupin protein fromRalstonia eutropha(PDB entry 3ebr).

Structure of two subfractions of normal porcine (Sus domesticus) serum low-density lipoproteins. X-ray small-angle scattering studies

Biochemistry ◽  
1981 ◽  
Vol 20 (11) ◽  
pp. 3231-3237 ◽  
Author(s):  
Guenther Juergens ◽  
Gabriele M. J. Knipping ◽  
Peter Zipper ◽  
Renata Kayushina ◽  
Gabor Degovics ◽  
...  
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
X Ray ◽  
Angle Scattering ◽  
Sus Domesticus

Low-Density Lipoproteins in Patients Homozygous for Familial Hyperbetalipoproteinaemia

1976 ◽  
Vol 51 (3) ◽  
pp. 221-231
Author(s):  
G. L. Mills ◽  
C. E. Taylaur ◽  
M. J. Chapman
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
Healthy Subjects ◽  
Diffusion Constant ◽  
Physicochemical Analysis ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Flotation Rate ◽  
Protein Moiety ◽  
And Diffusion

1. The low-density lipoproteins (LDL; density 1·007–1·063 g/ml) from two patients homozygous for familial hyperbetalipoproteinaemia have been submitted to chemical and physicochemical analysis. 2. The presence of an anomalous lipoprotein with a low proportion of triglyceride and a raised proportion of cholesterol has been confirmed. 3. In one patient, this lipoprotein accounted for about 85% of the LDL, but in the second, the amount varied from about 85% to a point at which it could not be detected among the coexisting normal lipoproteins. 4. The protein moiety of this anomalous LDL has effectively the same amino acid composition as that derived from the LDL of healthy subjects. 5. The proportions of carbohydrate, phospholipid and fatty acids could not be reliably distinguished from those of normal LDL. 6. The molecular weight and diffusion constant of the abnormal lipoprotein, even in the purest preparation, were close to the values determined for normal LDL of similar flotation rate.

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