Numerous eukaryotic cellular and viral proteins can be modified by the covalent attachment of fatty acyl groups. Protein acylation is classified into three types, viz., N-myristoylation, thioester (or ester) -linked acylation, and glycosylphosphatidylinositol-linked acylation. ProteinN-myristoylation involves the co-translational attachment of myristic acid (tetradecanoic acid, C14 : 0) to N-terminal glycine residues of various proteins. Myristoyl-CoA : proteinN-myristoyltransferase (NMT) is the enzyme by which the myristoyl group is transferred from myristoyl-CoA thioester toN-terminal glycine residues of nascent acylproteins. With consideration to the above, the syntheses of long-chain fatty acid analogs, especially myristic acid analogs, containing oxygen, sulfur, double bonds, triple bonds, aromatic residue, carbonyl, ester, and amide are reviewed. The structure-NMT activity relationship is also eluci-dated by using myristic acid analogs, N-terminal glycine-attached octapeptides, and Saccharomyces cervisiae NMT in vitro. The inhibition of the replication of human immunodeficiency virus-1 by these myristic analogs is briefly discussed.
Addition of the dodecanthiol cotelomer of vinyl pyrrolidone and methylacrylate (Ls-VPr-MA) to soap or a synthetic detergent as a builder gives rise to excellent detergency, particularly when high hardeness washing water is used. To determine the reasons for this, surface tension, permeability and chelating ability for aqueous solutions of sodium oleate, LAS (linear alkylbenzene sulfonate), Ls-VPr-MA telomer and an equimolar mixture of sodium oleate (or LAS) and telomer were measured. The surface tention of the equimolar mixture was less than that of a solution only of sodium oleate or telomer. The order of cmc was telomer<equimolar mixture<sodium oleate. Permeability of the surfactant solution to linen fabric was highest for an aqueous solution of the equimolar mixture. Chelating ability was high for an equimolar mixture of LAS and telomer due to formation of a complex with high interfacial activity. The present results may serve as the basis for methods to increase detergency by adding telomer to soap or a synthetic detergent.
Thermal oxidation of thin films of trilinoleoylglycerol (TLG) under air was investigated by termogravimetric analysis (TGA). Hydroperoxidative products of TLG film formed by thermal oxidation with TGA under air were converted to polymerization products quantitatively, during vacuum thermogravimetric analysis (VTGA). The following results were obtained : 1) Weight percent of hydroperoxidative products of TLG film (17 μm : thickness of film) obtained by programed heating under air was 1.04 wt %/°C and 80°C to 128°C. For film thickness of 85 μm, this parameter was 0.88 wt %/°C at 60°C to 120°C and 0.49 wt %/°C at 120°C to 145°C. 2) The relationship between TLG film thickness (17 μ m to 310 μm) and hydroperoxidative products (wt %) for maximum TLG film weight achieved by programed heating under air could be expressed quantitatively as 0.056 wt %/ μm. For less than 17 μm of thin films of TLG, hydroperoxidative product amounts greatly increased. 3) The initial logarithmic rate of the thermal oxidation of TLG film was proportional to the reciprocal of absolute temperature of the reaction. From Arrhenius plots apparent activation en ergy (ΔE ) of the TLG film (17 μm) oxidation was 8 kcal/mol and ΔE of the TLG film (85μ m) oxidation, 6 kcal/mol. 4) Qualitative assignment of thermal oxidative polymerization products was made at 100 and 200°C for 4 min, using thermograms of VTGA. The first peak corresponded to the dimer and its oxidation products and the second and third peaks, to the trimer and its oxidation products.
The dependence of limiting amounts of solubilized water on the concentrations of dodecyl tetra-, penta-, hexa-, and octaethylene glycol ethers (C12E4, C12E5, C12E 6, and C12E8) in cyclohexane was measured by Karl-Fisher titration at 25°C. Using 1H-NMR, fluorescence, and near infrared spectroscopic techniques, the states of water in solubilization regions except for C12E4 were examined as a function of Rw (= [H2O] / [surfactant]) at various surfactant concentrations. Two types of water were found present at various proportions in the interior of reversed micelles, i.e. waters is bound directly to oxyethylene groups of surfactants, and the succeeded water is held together with the hydrated oxyethylene groups by hydrogen bonds. Both were related to the formation of reversed and swollen micelles. Minimum Rw required for micelle formation was determined.
Neutral glycosphingolipids of the arthro-series were isolated from the porcine roundworm, Ascaris suum, Class Nematoda, Phylum Aschelminthes, Oligosaccharide structures of the glycolipids were completely characterized as Glc β1-Cer (CMS1 and CMS2), Man β1-4 Glc β1-Cer (CDS), GlcNAc β1-3 Man β1-4 Glc β1-Cer (CTS), GalNAc β1-4 GlcNAc β1-3 Man β1-4 Glc β1-Cer (CQS) and Gal α 1-3 GalNAc β1-4 GlcNAc β1-3 Man β1-4 Glc β1-Cer (CPS) by compositional analysis, methylation analysis, exoglycosidase hydrolysis, acid hydrolysis, chromium trioxide oxidation and TLC-immunostaining. The fatty acid and sphingoid compositions of CMS1, CDS, CTS, CQS and CPS were virtually the same, with those of 2-hydroxy C24 : 0-acid and branched heptadecasphingosine and heptadeca-4-sphingenine predominating. There would thus appear to be a comman metabolic pathway for CMS1 to CPS. However, CMS2 differed completely from the sphingoid components of other glycolipids with trihydroxy bases. Thin-layer chromatography and the results of sugar analysis indicated the presence of at least four minor glycolipids possessing large oligosaccharide chains each with six, seven sugars.
The phase behavior and HLB (three-phase) temperature of commercial poly (oxyethylene) nonionic surfactant were studied. HLB temperature of polydisperse poly (oxyethylene) nonionic surfactants shifted toward higher temperature with decreasing surfactant concentration and/or water/oil ratio due to differences in monodisperse solubilities (Si) of the surfactant in the excess oil phase. The relation between Si and surfactant composition in the surfactant phase (Sis) at the water-oil interface (within) the surfactant phase (middle-phase microemulsion) was determined based on the geo-metrical relation in phase equilibria. Si of the hydrophilic surfactant increased with temperature but decreased for the hydrophobic surfactant. Most commercial surfactants contain non-reactive alcohol and the distribution of hydrophilic chains is quite broad. Total monodisperse solubilities in oil (ΣSi) is thus quite large and HLB temperature changes considerably with surfactant concentration or water/oil ratio. For a long hydrocarbon-chain surfactant system, electrical conductivity is usuful for detecting HLB temperature applicable to phase study.
The antioxidative and synergistic effects of glycerophospholipids (PL) such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and phosphatidil-inositol (PI) were investigated using fish oil as a substrate at 30°C in the dark. PC was noted to express antioxidative effect, PE strong synergistic effect, PG proxidative effect and PI to have no effect at all. During autoxidation, mixed tocopherols added to the substrate were consumed in the order, α-, γ-δ-isomers, with or without PL. After the α-isomer disappeared, the γ-isomer started to be consumed, and then the δ-isomer. The remaining time of each tocopherol isomer in the PC or PE-containing substrate was prolonged 1.5 or 3 times that of the control group, respectively. The consumption rate of each tocopherol isomer was considered less in the substrate with PL than that of the control group because nitrogen-containing PL molecules, especially PE, easily release a hydrogen radical from the amino group to regenerate the corresponding tocopherol from tocopheryl radicals.