Jolivet Pascale, Boulard Céline, Chardot Thierry, Anton Marc
INRA, UMR 206, Chimie Biologique, F-78850 Thiverval-Grignon, France.
J Agric Food Chem. 2008 Jul 23;56(14):5871-9. doi: 10.1021/jf800321m. Epub 2008 Jun 18.
Apoproteins of low-density lipoproteins (LDL) and soluble proteins (livetins) contained in hen egg yolk plasma have been demonstrated as being essential to the interfacial and emulsifying properties of yolk. The knowledge of their structure is necessary to better understand these properties. Purified protein fractions were separated by SDS-PAGE or 2D-PAGE and identified through the LC-MS/MS of their trypsin peptides. Hen blood apolipoprotein B gives rise to nine different apoproteins in LDL after maturation and proteolysis. Among these apoproteins, two protein fragments appeared to be less accessible to proteases and could be enriched in beta-sheets and firmly associated with lipids. Plasma soluble proteins were constituted by approximately 45% of yolk immunoglobulins with a high heterogeneity of the variable regions of both heavy and light chains, 41% of glycoproteins constituted by YGP42 and YGP40, 14% of albumins, and one new minor protein we called YGP30, showing 75% similarity to YGP40.
鸡蛋黄血浆中含有的低密度脂蛋白（LDL）载脂蛋白和可溶性蛋白（livetins）已被证明对蛋黄的界面和乳化特性至关重要。了解它们的结构对于更好地理解这些特性是必要的。通过SDS-PAGE或二维聚丙烯酰胺凝胶电泳（2D-PAGE）分离纯化的蛋白质组分，并通过其胰蛋白酶肽段的液相色谱-串联质谱（LC-MS/MS）进行鉴定。母鸡血液载脂蛋白B在成熟和蛋白水解后在LDL中产生九种不同的载脂蛋白。在这些载脂蛋白中，有两个蛋白质片段似乎较难被蛋白酶作用，可能富含β-折叠并与脂质紧密结合。血浆可溶性蛋白约由45%的蛋黄免疫球蛋白组成，其重链和轻链可变区具有高度异质性，41%为由YGP42和YGP40组成的糖蛋白，14%为白蛋白，以及一种我们称为YGP30的新的次要蛋白，与YGP40具有75%的相似性。
