THE RELEASE OF CHOLESTEROL ESTERS FROM SERUM LIPOPROTEINS BY EXTRACTS OF CERTAIN GROUP A STREPTOCOCCI

Abstract

A chemical explanation has been provided for the production of opalescence in human and animal sera by extracts of certain Group A streptococci. Opalescence results from the selective liberation of specific lipids from α₁-serum lipoprotein. The released lipids have been quantitatively separated through the relatively simple technique of ultracentrifugal flotation, and subsequently analyzed by chemical and chromatographic means. Esterified cholesterol constitutes by far the major low density reaction product, accounting for 85 to 90 per cent of the total lipid released. A small amount of phospholipid (apparently limited to lecithin) was the only other lipid consistently found in low density product fractions.