PAPER ELEGTROPHORETIC CHARACTERIZATION OF PROTEINS AND LIPOPROTEINS OF HEN'S EGG YOLK

1962 ◽  
Vol 40 (7) ◽  
pp. 937-952 ◽  
Author(s):  
K. A. McCully ◽  
Chi-Ching Mok ◽  
R. H. Common
Keyword(s):  
Salt Solution ◽  
Egg Yolk ◽  
Complexing Agents ◽  
Low Density ◽  
Citrate Buffer ◽  
Density Fraction ◽  
Hen’S Egg ◽  
Veronal Buffer ◽  
Whole Egg

Staining for ester-linked protein phosphorus (ELPP) gave positive reactions with both of the main lipoprotein zones (P-1 and P-2) of paper electropherograms of egg yolk in certain buffers, including veronal buffer, pH 8.6. Treatment of the yolk with 1.0 M NaCl or with complexing agents (ethylenediaminetetraacetate, veronal–citrate buffer) resulted in the appearance of larger amounts of ELPP in the phosvitin (PT) zone. The distribution of the livetin zones suggested that the lipoprotein zone P-1 overlapped the greater part of the γ-livetin zone. This suggestion was supported by the results of immunoelectrophoretic experiments.Yolks in which the phosphorus had been labelled with P32 were separated by ultracentrifugation into (a) granule material; (b) low density fraction (LDF); and (c) the soluble livetin fraction. Paper electrophoretic studies of whole egg yolk and of these preparations showed (a) that the P-1 zone of electropherograms of whole egg yolk in veronal buffer comprised all of the LDF plus most of the γ-livetin plus a proportion of the phosvitin that depended on the strength of the salt solution used to disperse the yolk, the nature of the buffer, and the absence or presence of complexing agents; and (b) that the P-2 zone comprised the lipovitellin fraction together with more or less of the phosvitin. Dispersion of the yolk in 1.0 M NaCl, pretreatment of the yolk with ethylenediaminetetraacetate, or use of veronal–citrate buffer led to the appearance of relatively high proportions of the total protein-bound phosphorus and P32 in the 'fast' phosvitin (PT) zone.

PAPER ELEGTROPHORETIC CHARACTERIZATION OF PROTEINS AND LIPOPROTEINS OF HEN'S EGG YOLK

1962 ◽  
Vol 40 (1) ◽  
pp. 937-952 ◽  
Author(s):  
K. A. McCully ◽  
Chi-Ching Mok ◽  
R. H. Common
Keyword(s):  
Salt Solution ◽  
Egg Yolk ◽  
Complexing Agents ◽  
Low Density ◽  
Citrate Buffer ◽  
Density Fraction ◽  
Hen’S Egg ◽  
Veronal Buffer ◽  
Whole Egg

Staining for ester-linked protein phosphorus (ELPP) gave positive reactions with both of the main lipoprotein zones (P-1 and P-2) of paper electropherograms of egg yolk in certain buffers, including veronal buffer, pH 8.6. Treatment of the yolk with 1.0 M NaCl or with complexing agents (ethylenediaminetetraacetate, veronal–citrate buffer) resulted in the appearance of larger amounts of ELPP in the phosvitin (PT) zone. The distribution of the livetin zones suggested that the lipoprotein zone P-1 overlapped the greater part of the γ-livetin zone. This suggestion was supported by the results of immunoelectrophoretic experiments.Yolks in which the phosphorus had been labelled with P32 were separated by ultracentrifugation into (a) granule material; (b) low density fraction (LDF); and (c) the soluble livetin fraction. Paper electrophoretic studies of whole egg yolk and of these preparations showed (a) that the P-1 zone of electropherograms of whole egg yolk in veronal buffer comprised all of the LDF plus most of the γ-livetin plus a proportion of the phosvitin that depended on the strength of the salt solution used to disperse the yolk, the nature of the buffer, and the absence or presence of complexing agents; and (b) that the P-2 zone comprised the lipovitellin fraction together with more or less of the phosvitin. Dispersion of the yolk in 1.0 M NaCl, pretreatment of the yolk with ethylenediaminetetraacetate, or use of veronal–citrate buffer led to the appearance of relatively high proportions of the total protein-bound phosphorus and P32 in the 'fast' phosvitin (PT) zone.

Characterization of glycopeptides derived from the low-density lipoprotein of hen's egg yolk

1968 ◽  
Vol 46 (8) ◽  
pp. 983-988 ◽  
Author(s):  
J. Z. Augustyniak ◽  
W. G. Martin
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Egg Yolk ◽  
Low Density ◽  
Amide Nitrogen ◽  
Acetylneuraminic Acid ◽  
Hen’S Egg ◽  
Terminal Amino ◽  
Protein Moiety

Two glycopeptides (A and B) were isolated from pronase-digested vitellenin, the protein moiety of the low-density lipoprotein of hen's egg yolk. Aspartic acid was the only N-terminal amino acid of both glycopeptides but only A contained N-acetylneuraminic acid. A contained 55% hexose (mannose), 14% hexosamine, 12% N-acetylneuraminic acid, 0.71% amide nitrogen, and its molecular weight was 2.3 × 103. The corresponding values for B were 64, 17, 0.0, 0.75, and 2.0 × 103. Chemical analyses showed that B (and probably A) occurs in vitellenin with the heteropolysaccharide group bound N-glycosidically via the β-amide group of an asparaginyl residue. The indicated structure is R∙(NH)Asp∙Thr∙Ser∙(Ala, Gly, Val)∙Ile, where R, the heteropolysaccharide group, contains 2 hexosamine and 8 hexose residues.

THE MACROMOLECULAR COMPOSITION OF HEN'S EGG YOLK AT SUCCESSIVE STAGES OF MATURATION

1967 ◽  
Vol 45 (4) ◽  
pp. 591-601 ◽  
Author(s):  
S. L. Mackenzie ◽  
W. G. Martin
Keyword(s):  
Soluble Fraction ◽  
Early Period ◽  
Egg Yolk ◽  
Water Soluble ◽  
Low Density ◽  
Yolk Formation ◽  
Water Soluble Fraction ◽  
Density Fraction ◽  
Hen’S Egg ◽  
Macromolecular Composition

Yolk at different stages of its formation was separated into its major macromolecular fractions, namely, granules, low-density fraction (LDF), and water-soluble fraction (WSF), and the components of these fractions were examined by ultracentrifugal, electrophoretic, and chromatographic methods. Total yolk solids and the amounts of the several fractions all increased exponentially during yolk formation but at differential rates for different fractions. The proportion of LDF increased rapidly to a maximum (76% of total solids) for yolks weighing 2–5 g, and then declined. Both the WSF and granule fractions decreased in proportion during the early period of yolk formation and then increased slightly as yolk neared maturity. Of the WSF components, the proportions of α-livetin (serum albumin) and β-livetin increased somewhat and γ-livetin (serum γ-globulin) decreased slightly, during yolk maturation. The major granule subfraction, PvLv, showed an increased proportion of phosvitin and α-lipovitellin relative to β-lipovitellin during yolk formation. This increase in the proportions of the phosphorus-rich proteins was not paralleled by a corresponding increase in PvLv phosphorus, which suggests that other phenomena may be involved.

LIPID EXTRACTION AND DISTRIBUTION STUDIES OF EGG YOLK LIPOPROTEINS

1963 ◽  
Vol 41 (1) ◽  
pp. 657-666 ◽  
Author(s):  
W. G. Martin ◽  
N. H. Tattrie ◽  
W. H. Cook
Keyword(s):  
Fatty Acid ◽  
Neutral Lipids ◽  
Lipid Extraction ◽  
Egg Yolk ◽  
Low Density ◽  
Cholesterol Esters ◽  
Density Fraction ◽  
Distribution Studies ◽  
Egg Yolk Lipoproteins ◽  
Fatty Acid Compositions

The three lipoproteins of egg yolk, α- and β-lipovitellin and the low-density fraction (LDF), have been isolated and their lipid compositions determined. α- and β-lipovitellin comprise 22 to 26% lipid, of which 61% is phospholipid, 35% is triglyceride, and 4% is cholesterol and its esters. LDF contains about 89% lipid having 27% phospholipid, 69% triglyceride, and 4% cholesterol and cholesterol esters. The phospholipids of the three lipoproteins are similar, i.e., 74% lecithins, 18% cephalins, and 8% minor phospholipids. The fatty acid compositions of the neutral lipids, lecithins, and cephalins of the α- and β-lipovitellins were also similar, with only minor differences.Gentle extraction of the LDF solutions with ethyl ether readily removes about 85% of the total lipid and 55% of the phospholipid, while subsequent changes are slow. The lipoprotein residue contains 52% lipid which is mostly phospholipid; when the residual ether is removed, five sedimenting components are observed in the ultracentrifuge.

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