The extreme thermophile (Thermus thermophilus 111) isolated from a hot spring water was cultured to obtain lipase. The lipase was purified from an extracellular extract and examination was made of some of its properties. Its maximum activity was expressed at pH 7.0 and 65°C. The addition of Ca2+ ions to the reaction mixture increased the rate of hydrolysis. The longer acyl chain was hydrolyzed more quickly than the shorter acyl chain by the lipase. Lipase thermostability was so high that as much as 85 % of the initial activity remained after 10 min at 100°C.
Explanation has been made for thermo-rheological properties of mixture systems of 1, 3-dioleoyl-2-stearoylglycerol (OSO) /cocoa butter, and dark chocolate involving OSO. A OSO/cocoa butter mixture was shown to form a compound at a ratio such that the sum total amount of POP (P : palmitoyl), POS and SOS in cocoa butter was the same as that of OSO equal. X-ray diffraction patterns showed the stable form of the compound to possess a double chain length structure. Stress values required for constant strain were determined with a rheometer at different temperatures. The OSO/cocoa butter compound showed stress values much less than that of the compound formed by OSO/SOS. Lowering stress values in OSO/cocoa butter would thus possibly be due to interactions between compound crystals and the liquid oil fraction in the cocoa butter. Possible molecular mechanisms of the interactions are discussed based on the relationship of double chain length lamellar structures to lamellar slipping movement induced by the incorporation of liquid oil at the lamellar interface.
The thermal oxidative polymerization and degradation of thin films of trioleoylglycerol (TOG) under an air were investigated by vacuum thermogravimetric analysis (VTGA) using dynamic thermal programs. The following results were obtained : 1) The logarithmic initial rate of the thermal oxidative polymerization of TOG was in proportion to the recipocal of the absolute temperature of the reaction. From Arrhenius plots, apparent activation energies were 29 and 9 kcal/mol at 80°C to 130°C and 140°C to 230°C, respectively. 2) The composition of the thermal oxidative polymer of TOG was determined from a curve of the rate of weight loss from 270°C to 450°C. 3) The relationship between logarithmic initial rate of thermal oxidative degradation and reciprocal of the reaction temperature of TOG could be expressed as an expression of proportion.
Monoesters from maleic anhydride and ethylene oxide adducts of C1214s-alcohols (EOAA) were found in this study to be quantitative yield at a reaction temperature lower than 70°C with a sodium acetate catalyst. At a reaction temperature exceeding 100°C, the diesters formed by successive reaction lowered the yield of the monoesters. The present results were obtained by potentiometry for determination of total acid, maleic acid and monoster. The reaction kinetics are also discussed.
Squalene hydroperoxide present in human skin surface lipids was examined by a chemiluminescence high performance liquid chromatography (CL-HPLC) system. A mixture of cytochrome c and luminol served as the hydroperoxide-specific luminescence reagent for post-column detection in reversed phase HPLC. Squalene hydroperoxide was previously detected in skin surface lipids of the human forehead following exposure to the sun. Therefore, in this study, squalene monohydroperoxide was prepared by dye-sensitized photooxidation and its chemical structure was determined by 1H-NMR, 13C-NMR, and FAB-MS. The detection limit of squalene monohydroperoxide in CL-HPLC system was as low as 1 pmol. Skin surface lipids from forehead, scalp, and dandruff were also studied. By exposure to sun light or after washing with shampoo, squalene monohydroperoxide could be detected in nearly all samples examined. Squalene may thus be considered the first target lipid on human skin surface that incurs oxidative stress by sun light exposure, etc.
Synthetic routes were established for amphiphilic compounds containing (η4-diene) Fe (CO) 3 as a lipophilic group and ammonium or sulfonium group as a hydrophilic group from 2, 4-hexadienoic acid and Fe (CO) 5 as starting materials. The ammonium salt, [CH3CH=CHCH=CHCO2 C6H4N+Me3] Fe (CO) 3I- (3) and sulfonium salt [CH3CH=CHCH=CHCO2C6H4S+Me2] Fe (CO) 3 MeSO4- (7) thus obtained were found soluble in water and polar organic solvents and stable in solvents. Reaction of (3) and (7) with amines in water-acetonitrile solution led to the conversion of the ester group to an amide group in good yield. The reaction of (3) with octylamine was depended on the water/acetonitrile ratio of the solvent. The yield of amide was maximum at a water/acetonitrile ratio of 3. Equilibrium between the ammonium salt and its free amine would appear to be the cause for the solvent effects. However, amide yield in the reaction of (7) with ocatylamine was virtually constant regardless of the solvent ratio.
Examination was made of the thermal oxidation of thin films (33120 μ m) of trilinolenoyl-glycerol (TLNG) with and without methyl polysiloxane (SO ; 1000 ppm) under an oxygen atomosphere thermal gravimetric analysis using thermal programs (5°C/min). The following results were obtained : 1) The rate of residual weight of TLNG (RRW TLNG) with SO exceeded that of TLNG without SO in the temperature range, 170 to 300°C. 2) The temperature of the maindecomposition of TLNG with SO was higher than that of TLNG without SO. 3) For film samples of thickness from 50 to 120 μ m, the relationship between temperature and effect of heat-resistance of TLNG with and without SO is apparent from the following data :