Lecithins from egg yolk, yeast, bovine lung, bovine livers, and hog livers were analyzed for the fatty acids in the α and β positions after hydrolysis of the fatty acids in the β position with phospholipase A. The maximum and minimum values for the four types of lecithins, viz. (1) disaturated, (2) α-saturated-β-unsaturated, (3) α-unsaturated-β-saturated, and (4) diunsaturated, were calculated for the above five lecithins and many more from data reported by other laboratories. Some of the results from some lecithins suggest that the fatty acids found in the α position may be randomly distributed with those found in the β position.
A novel C(35) terpene and its monounsaturated analogue were isolated from cultures of Acetobacter xylinum, together with traces of their C(36) homologues. These substances were found to be hopane derivatives substituted by a five-carbon chain bearing four vicinal hydroxyl groups. For the parent hydrocarbon the term bacteriohopane is proposed. The elucidation of the structures utilized high-resolution mass spectrometry of the terpenes, degradation to C(32) hydrocarbons and detailed mass-spectrometric comparison of these with C(32) hydrocarbons synthesized from known pentacyclic triterpenes. High-resolution mass-spectral data of the terpenes are presented. N.m.r. data are in agreement with the proposed structures, which are further supported by the isolation from the same organism of 22-hydroxyhopane and derivative hopene(s).
I'he three lipoproteins of egg yolk, a-and p-lipovitellin and the low-density fraction (LDF), have been isolated and their lipid compositions determined. a-and p-lipovitellin comprise 22 to 2670 lipid, of which 6 l y O is phospholipid, .35(,% is triglyceride, and 4y0 is cholesterol and its esters. L D F contains about 89(y0 lipid having 27y0 phospholipid, 69y0 triglyceride, and 4y0 cholesterol and cholesterol esters. The phospholipids of the three lipoproteins are similar, i.e., 74'% lecithins, 18% cephalins, and 870 minor phospholipids. The fatty acid coinpositiolls of the neutral lipids, lecithins, and cephalins of the a-and p-lipovitellins were also similar, with only minor differences. Gentle extraction of the L D F solutions with ethyl ether readily removes about 85y0 of the total lipid and 55Yo of the phospholipid, while subsequent changes are slow. 'I'he lipoprotein residue contains 5270 lipid which is mostly phospholipid; \\,hen the residual ether is removed, five sedi~nenting components are observed in the ultracentrifuge. 1Issued as N.R.C. No. 7144. Can. J. Biochem. Physiol. Downloaded from www.nrcresearchpress.com by STOCKHOLMS UNIVERSITET on 08/07/15 For personal use only.
The three lipoproteins of egg yolk, α- and β-lipovitellin and the low-density fraction (LDF), have been isolated and their lipid compositions determined. α- and β-lipovitellin comprise 22 to 26% lipid, of which 61% is phospholipid, 35% is triglyceride, and 4% is cholesterol and its esters. LDF contains about 89% lipid having 27% phospholipid, 69% triglyceride, and 4% cholesterol and cholesterol esters. The phospholipids of the three lipoproteins are similar, i.e., 74% lecithins, 18% cephalins, and 8% minor phospholipids. The fatty acid compositions of the neutral lipids, lecithins, and cephalins of the α- and β-lipovitellins were also similar, with only minor differences.Gentle extraction of the LDF solutions with ethyl ether readily removes about 85% of the total lipid and 55% of the phospholipid, while subsequent changes are slow. The lipoprotein residue contains 52% lipid which is mostly phospholipid; when the residual ether is removed, five sedimenting components are observed in the ultracentrifuge.
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