The plasma membrane fraction of rat liver was isolated and incubated with labeled lysophosphatides in the presence of cofactors; the acylation of lysolecithin to lecithin by the fraction was compared to that of the rough and smooth microsomes. The purity of the isolated fractions was ascertained by enzyme markers and electron microscopy, and the maximal contamination of the plasma membrane frac...

This paper is concerned with the nature of the hemolytic material which occurs in certain tumors, and particularly with the question whether it dif fers from the hemolytic material found in many normal tissues. The latter, at least in one of its forms, has been shown to have the characteristics of soaps and of lysolecithin-like substances more or less loosely combined with inhibitory material i...

The report of Oakley, Warrack, and Clarke (1947) on the toxins of the Clostridium novyi (oedematiens) group and of Clostridium hemolyticum indicates the complexity of this topic and presents the pertinent historical data. It is known that the toxins C. novyi and C. hemolyticum involve a lecithinase catalyzing the hydrolysis of lecithin to phosphorylcholine and a diglyceride. In view of the exis...

Phospholipase B has been found in the mosquito Culex pipiens fatigans, and some of its properties have been studied. The enzyme had a high optimum temperature (45 degrees C) and broad alkaline pH optimum (8-9). It was inactive toward diacylphospholipids, and hydrolyzed lysolecithin at a higher rate than lysophosphatidyl ethanolamine. The enzyme was heat labile, but lysolecithin protected it aga...

Relapsing fever borreliae require lipid compounds for growth in vitro. In this study, the major pathways of lipid catabolism in three species of tick-borne relapsing fever borreliae were investigated. Thin-layer chromatography was used to compare chloroform-methanol extracts of fresh culture media with extracts of exhausted culture media after organisms were removed by centrifugation. The chrom...

The lipid composition of human chylomicrons has been studied using blood collected from normal male volunteers after ingestion of 200 g of butter fat. The concentration of chylomicrons in the blood samples varied widely among 12 subjects but in each case the following lipids were present : triglycerides, diglycerides (probably the 1,2-isomers), monoglycerides, free and esterified cholesterol, t...