Characterization of lipoprotein fractions with high content of hemocyanin in the hemolymphatic plasma ofPolybetes pythagoricus
✍ Scribed by Cunningham, Mónica; Pollero, Ricardo J.
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 606 KB
- Volume
- 274
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
In order to evaluate the role of hemocyanin in the hemolymphatic transport of lipids, two hemocyanin-containing lipoprotein fractions, a very-high-density lipoprotein (VHDL) and a high-density lipoprotein (HDL) isolated from plasma of the spider Polybetes pythagoricus, were characterized. VHDL concentration was found to be twofold when compared to that of HDL, and both of them transport 70% of total circulating lipids. Their lipid moieties were mainly composed of phospholipids (65% and 55% in VHDL and HDL, respectively), triacylglycerols, and free fatty acids in a minor degree, and diacylglycerols, cholesterol, and hydrocarbons even in lesser amounts. Although hemocyanin was the predominant apoprotein, two other proteins were also present in minor amounts, especially in VHDL. The two lipoproteins were analyzed by gel filtration chromatography and separated into three subfractions. Two of them were composed of the heptamer (500 kDa) and the monomer (70 kDa) of hernocyanin, respectively, and different proportions of binding lipids. Free fatty acids (37% of total subfraction lipids) were the main lipid classes linked to the heptamer, whereas triacylglycerols (24%) and free fatty acids (22%) predominated among lipids associated with the hemocyanin monomer, The third subfraction contained the hexamer of hemocyanin (420 m a ) , two minor polypeptides, and 65% of the VHDL total lipids. This subfraction is the principal means of transport of phosphatidylcholine and triacylglycerols in VHDL. It is here suggested that hemocyanin, as a single apoprotein or associated with other polypeptides, is responsible for the transport of the majority of plasma lipids in this invertebrate.