ABSTRACT
Porcine omental lipid extracts were fractionated and the major lipid components characterized. Approximately 97% of the chloroform/methanol extract consisted of triglycerides containing primarily 16:0, 18:0, 18:1, and 18:2 fatty acids. Small quantities of free fatty acids, cholesterol, di- and monoglycerides were also detected. The phospholipid fraction, obtained by solvent partition and Unisil column chromatography and characterized by high performance liquid chromatography (HPLC) and HPLC-mass spectrometry, was found to consist primarily of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol. The neutral glycolipids, isolated by solvent partition and Unisil column chromatography and identified by HPTLC and HPLC, were found to consist primarily of di-, tri- and tetraosylceramides. The complex glycolipid fraction, obtained from Folch upper phase solvent partition and characterized by HPTLC and immunoblotting, was found to consist primarily of ganglio-, globo-, and neolacto- neutral glycolipids and ganglio-, globo-, neolacto- and fucosylated gangliosides.
Subject(s)
Lipids/analysis , Omentum/physiology , Animals , Chromatography, High Pressure Liquid , Fatty Acids/analysis , Gangliosides/analysis , Glycolipids/analysis , Immunoblotting , Phospholipids/analysis , Swine , Triglycerides/analysisABSTRACT
Irradiation of nitric oxide myoglobin (NOMb) induces changes in the haem as well as protein moiety of NOMb, especially at doses of 400-800 krad. The changes in the protein include: Conformational changes, with apparent partial denaturation of globin alpha-helix as evidenced by circular dichroism. Preferential scission of the polypeptide chain and dimerization via covalent bond(s) as evidenced by SDS-polyacrylamide gel electrophoresis. Products with a spectrum of hydrodynamic volumes between those of the monomer and the dimer are also formed. The shift of NOMb pIs toward more acidic pHs (probably due to modification and/or destruction of basic amino acid residues by water radiolytic products) as evidenced by isoelectric focusing.
Subject(s)
Food Irradiation , Globins/radiation effects , Myoglobin/analogs & derivatives , Animals , Cattle , Circular Dichroism , Electrophoresis, Polyacrylamide Gel , Gamma Rays , Isoelectric Focusing , Myoglobin/radiation effectsABSTRACT
Bovine nitric oxide myoglobin (NOMb) was irradiated with 40-4000 krad of gamma-radiation, and the effects on the haem studied using absorption spectroscopy and electron spin resonance (e.s.r.) spectroscopy. The results show the following behaviour. The bright red colour of NOMb changes to brown upon irradiation. This is similar to changes observed in radiation sterilized. nitrite-containing meats. NOMb becomes progressively denitrosylated, with met-myoglobin (metMb) as the immediate product. Upon increasing doses of radiation (up to 800 krad) at 0 degrees C parallel to NOMb denitrosylation, metMb is gradually converted, by water radiolytic products, to other products, believed to be ferromyoglobin and ferrimyoglobin peroxide. A minor quantity of 'choleglobin-type' pigments may also be formed at the highest doses. Freezing of NOMb has a substantial protective effect against radiation. Native bovine NOMb behaves as a pentaco-ordinate (hfs of 3 peaks with equal intensity); the bond between iron and N epsilon is thus dramatically stretched and weakened. Using a thermal energy analyser, no NO could be detected over irradiated NOMb solution, indicating rapid reaction of NO liberated from NOMb by radiation, with radiolytic products of water.
