Structure of egg yolk very low density lipoprotein. Polydispersity of the very low density lipoprotein and the role of lipovitellenin in the structure

Evans, Robert J.; Bauer, Dierk; Bandemer, Selma L.; Vaghefi, Simin B.; Flegal, Cal J.

doi:10.1016/0003-9861(73)90001-5

Cited by 35 publications

(16 citation statements)

References 20 publications

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“…The isolated EY-LDF showed similarities with those reported by earlier workers [48][49][50]. The chromatographic separation of the isolated LDF resulted in two lipoprotein fractions (LDF-I and LDF-II; Figs.…”

Section: Discussionsupporting

confidence: 74%

Major Proteins of Bovine Seminal Plasma Bind to the Low-Density Lipoprotein Fraction of Hen's Egg Yolk1

Manjunath

Nauc

Bergeron

et al. 2002

Biology of Reproduction

173

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Over the past 60 years, egg yolk (EY) has been routinely used in both liquid semen extenders and those used to cryopreserve sperm. However, the mechanism by which EY protects sperm during liquid storage or from freezing damage is unknown. Bovine seminal plasma contains a family of proteins designated BSP-A1/-A2, BSP-A3, and BSP-30-kDa (collectively called BSP proteins). These proteins are secretory products of seminal vesicles that are acquired by sperm at ejaculation, modifying the sperm membrane by inducing cholesterol efflux. Because cholesterol efflux is time and concentration dependent, continuous exposure to seminal plasma (SP) that contains BSP proteins may be detrimental to the sperm membrane, which may adversely affect the ability of sperm to be preserved. In this article, we show that the BSP proteins bind to the low-density fraction (LDF), a lipoprotein component of the EY extender. The binding is rapid, specific, saturable, and stable even after freeze-thawing of semen. Furthermore, LDF has a very high capacity for BSP protein binding. The binding of BSP proteins to LDF may prevent their detrimental effect on sperm membrane, and this may be crucial for sperm storage. Thus, we propose that the sequestration of BSP proteins of SP by LDF may represent the major mechanism of sperm protection by EY.

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Section: Discussionsupporting

confidence: 74%

Major Proteins of Bovine Seminal Plasma Bind to the Low-Density Lipoprotein Fraction of Hen's Egg Yolk1

Manjunath

Nauc

Bergeron

et al. 2002

Biology of Reproduction

173

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“…Martin et al (1959) showed that the protein moieties of yolk LDL have two or more polypeptide chains. Evans et al (1973) suggest that yolk LDL is similar to serum VLDL rather than serum LDL owing to its high lipid content. Evans et al (1973) suggest that yolk LDL is similar to serum VLDL rather than serum LDL owing to its high lipid content.…”

Section: Introductionmentioning

confidence: 97%

Isolation and Fractionation of the Protein Moiety of Egg Yolk Low Density Lipoprotein

Nakamura¹,

Hayakawa²,

Satô³

1977

Poultry Science

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The protein moiety of egg yolk LDL was a mixture of glycoproteins which separated into several bands by SDS polyacrylamide gel electrophoresis. The main component was a large protein of 130,000 molecular weight, and represented over 70% of the total proteins. Among other components, the smallest protein made up about 20% of total proteins and had a molecular weight of 15,000. Remaining components included at least four proteins with molecular weights in the range of 60,000-95,000. The main protein and the smallest protein could be separated from other components by gel filtration on Sepharose 4B. Although their amino acid composition was almost the same, their carbohydrate content was different. Other components besides these two proteins were assumed to be derived from the main protein during the preparation of delipidation.

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“…12) Because PC and PE, the major phopholipids of lipoproteins such as lipovitellin and lipovitellenin, 17) are not contained in EP (Fig. 2), it is inferred that EP is different from lipovitellin and lipovitellenin.…”

Section: Discussionmentioning

confidence: 99%

Effects of Proteins from Hen Egg Yolk on Human Platelet Aggregation and Blood Coagulation

Cho

Ham

Lee

et al. 2003

Biological & Pharmaceutical Bulletin

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It is known that platelet aggregation and blood coagulation are common risk factors for pathologic phenomena in cardiovascular disease. Antiplatelet drugs, such as theophylline and verapamil, decrease the concentration of cytosolic free Ca 2ϩ by elevating the level of cyclic-adenosine monophosphate (cAMP).2) Vasodilators, such as molsidomine, nitroprusside, and nitroglycerine, inhibit the activation of platelets by elevating the cyclic-guanosine monophosphate (cGMP) concentration. 3,4) Egg yolk proteins have been recognized to be beneficial to health for a long time. However, there are adverse reports that the proteins of egg yolk are composed of allergens such as lipovitellenin and livetin. 5,6) Another harmful substance of hen eggs is cholesterol, which affects serum cholesterol levels. Egg cholesterol is known to be contained only in the yolk.7) Interestingly, in our studies, we found that proteins from hen egg yolk (EP) did not contain allergenic proteins and cholesterol (Fig. 1, 2B-5). Accordingly, we investigated whether EP has antiplatelet and anticoagulation effects compared with those of theophylline and molsidomine, which elevate cAMP and cGMP, respectively. MATERIALS AND METHODS Materials Preparation of Protein Extracts from Hen Egg YolksHen eggs were purchased from a local market and the yolks were collected. A total 20 g of egg yolk was homogenized with extraction solvents (chloroform/methanol 2 : 1, v/v) using the method of Folch et al.,8) and then extracted three times with extraction solvents using an extraction mixer (Lab-Line Instruments, Inc.). After centrifugation, the lower layer was collected, frozen at Ϫ80°C, and then lyophilized for 24 h. This dehydrated substance was dissolved and extracted in solvent (chloroform/distilled water 1 : 1, v/v). After centrifugation, the chloroform layer and aqueous layer were separated. The aqueous layer was filtered with a centrifuge filter device (Amicon Centricon YM-10, Millipore, Beford, MA, U.S.A.). The lower layer was frozen at Ϫ80°C and then lyophilized for 24 h. This dehydrated substance was dissolved in distilled water when assayed.Separation and Identification of EP EP containing an equal volume of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) buffer (5% mercaptoethanol, 2% SDS, 10% glycerol, 0.0625 M Tris, 0.01% bromphenol blue, pH 6.8) was boiled for 5 min to denature the proteins completely. The proteins were separated by SDS-PAGE (17%, 1.0 mm gel) according to the method of Laemmli. 9)Separated proteins were stained with silver stain (Silver Stain Plus, Bio-Rad Laboratories) and dried. The relative intensity of protein bands was analyzed using SigmaGel TM Gel Analysis Software (Jandel, Scientific Software, U.S.A.). Molecular weight standards were used as low-range protein size markers in silver stain.Preparation of Human Washed Platelets Blood from healthy human volunteers was anticoagulated by 10% ACD solution (0.8% citric acid, 2.2% sodium citrate, 2.45% glucose). Platelet-rich plasma (PRP) was obtained by centrifugat...

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Structure of egg yolk very low density lipoprotein. Polydispersity of the very low density lipoprotein and the role of lipovitellenin in the structure

Cited by 35 publications

References 20 publications

Major Proteins of Bovine Seminal Plasma Bind to the Low-Density Lipoprotein Fraction of Hen's Egg Yolk1

Major Proteins of Bovine Seminal Plasma Bind to the Low-Density Lipoprotein Fraction of Hen's Egg Yolk1

Isolation and Fractionation of the Protein Moiety of Egg Yolk Low Density Lipoprotein

Effects of Proteins from Hen Egg Yolk on Human Platelet Aggregation and Blood Coagulation

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