The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Kenichi Akaji - One of the best experts on this subject based on the ideXlab platform.
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A Reductive Acidolysis Final Deprotection Strategy in Solid Phase Peptide Synthesis Based on Safety-Catch Protection
Chemical & pharmaceutical bulletin, 1997Co-Authors: Tooru Kimura, Shigeki Tanaka, Toshio Fukui, Kenichi Akaji, Yoshiaki KisoAbstract:A reductive Acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch type of semi-permanent protecting groups and new linkers which were derived from 4-methylsulfinylbenzyl protection. This new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive Acidolysis-cleavable semi-permanent protecting groups. By using this strategy, we successfully synthesized four model peptides, of which two contained C-terminal amide.
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A new reductive Acidolysis final deprotection strategy in solid phase peptide synthesis. Use of a new safety-catch linker
Tetrahedron Letters, 1994Co-Authors: Yoshiaki Kiso, Toshio Fukui, Shigeki Tanaka, Tooru Kimura, Kenichi AkajiAbstract:Abstract A new reductive Acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch linker; this new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive Acidolysis-cleavable semipermanent protecting groups.
Fereidoon Shahidi - One of the best experts on this subject based on the ideXlab platform.
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Acidolysis of p-coumaric acid with omega-3 oils and antioxidant activity of phenolipid products in in vitro and biological model systems.
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Jiankang Wang, Fereidoon ShahidiAbstract:Lipase-catalyzed Acidolysis of p-coumaric acid with seal blubber oil (SBO) and menhaden oil (MHO) was carried out, followed by identification of major phenolipids in the resultant Acidolysis mixture using high-performance liquid chromatography/mass spectrometry. Separation of phenolipid components from the resultant Acidolysis mixture was achieved using flash column chromatography. The antioxidant activities of the phenolipids were examined in in vitro assays and biological model systems. The major phenolipids identified from Acidolysis mixtures with both SBO and MHO included eight phenolic monoacylglycerols and eight phenolic diacylglycerols. Phenolipids derived from SBO and MHO generally showed good antioxidant potential in the systems tested. The prepared phenolipids exhibited high scavenging capacity toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxyl radicals and displayed reducing power, strong inhibitory effect on bleaching of β-carotene, human low-density lipoprotein (LDL) cholesterol oxidatio...
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structured lipids via lipase catalyzed incorporation of eicosapentaenoic acid into borage borago officinalis l and evening primrose oenothera biennis l oils
Journal of Agricultural and Food Chemistry, 2002Co-Authors: S Namal P J Senanayake, Fereidoon ShahidiAbstract:Enzymatic Acidolysis of borage oil (BO) or evening primrose oil (EPO) with eicosapentaenoic acid (20:5n−3; EPA) was studied. Of the six lipases that were tested in the initial screening, nonspecific lipase PS-30 from Pseudomonas sp. resulted in the highest incorporation of EPA into both oils. This enzyme was further studied for the influence of enzyme load, temperature, time, type of organic solvent, and mole ratio of substrates. The products from the Acidolysis reaction were analyzed by gas chromatography (GC). The highest incorporation of EPA in both oils occurred at 45−55 °C and at 150−250 enzyme activity units. One unit of lipase activity was defined as nanomoles of fatty acids (oleic acid equivalents) produced per minute per gram of enzyme. Time course studies indicated that EPA incorporation was increased up to 26.8 and 25.2% (after 24 h) in BO and EPO, respectively. Among the solvents examined, n-hexane served best for the Acidolysis of EPA with both oils. The effect of the mole ratio of oil to EPA...
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structured lipids via lipase catalyzed incorporation of eicosapentaenoic acid into borage borago officinalis l and evening primrose oenothera biennis l oils
Journal of Agricultural and Food Chemistry, 2002Co-Authors: S Namal P J Senanayake, Fereidoon ShahidiAbstract:Enzymatic Acidolysis of borage oil (BO) or evening primrose oil (EPO) with eicosapentaenoic acid (20:5n-3; EPA) was studied. Of the six lipases that were tested in the initial screening, nonspecific lipase PS-30 from Pseudomonas sp. resulted in the highest incorporation of EPA into both oils. This enzyme was further studied for the influence of enzyme load, temperature, time, type of organic solvent, and mole ratio of substrates. The products from the Acidolysis reaction were analyzed by gas chromatography (GC). The highest incorporation of EPA in both oils occurred at 45-55 degrees C and at 150-250 enzyme activity units. One unit of lipase activity was defined as nanomoles of fatty acids (oleic acid equivalents) produced per minute per gram of enzyme. Time course studies indicated that EPA incorporation was increased up to 26.8 and 25.2% (after 24 h) in BO and EPO, respectively. Among the solvents examined, n-hexane served best for the Acidolysis of EPA with both oils. The effect of the mole ratio of oil to EPA was studied from 1:1 to 1:3. As the mole ratio of EPA increased, the incorporation increased from 25.2-26.8 to 37.4-39.9% (after 24 h). The highest EPA incorporations of 39.9 and 37.4% in BO and EPO, respectively, occurred at the stoichiometric mole ratio of 1:3 for oil to EPA.
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enzyme catalyzed synthesis of structured lipids via Acidolysis of seal phoca groenlandica blubber oil with capric acid
Food Research International, 2002Co-Authors: S. P. J. Namal Senanayake, Fereidoon ShahidiAbstract:Abstract A structured lipid (SL) containing n-3 fatty acids (eicosapentaenoic acid, 20:5n-3; docosahexaenoic acid, 22:6n-3) and capric acid (10:0; a medium chain fatty acid) was prepared using lipase-catalyzed Acidolysis of seal blubber oil with capric acid. An immobilized lipase, Lipozyme-IM from Mucor miehei, was used as the biocatalyst. Acidolysis reactions were carried out in hexane and the products were analyzed by gas chromatography. Incorporation of capric acid was affected by mole ratio of substrates, type of organic solvent, reaction temperature, reaction time, water content and the amount of lipase. The optimum reaction mixture and conditions were oil/fatty acid mole ratio of 1:3, hexane, 45 °C, 24 h, 1% (w/w of substrates) water and 10% (w/w of substrates) Lipozyme-IM lipase. Under these conditions, a SL containing 2.3% 20:5n-3, 7.6% 22:6n-3 and 27.1% 10:0 was obtained. Solvents with log P values between 2.5 and 4.5 performed the Acidolysis reaction better than those with log P values of less than 2.5. However, in the absence of any organic solvent, Lipozyme-IM afforded a satisfactory incorporation of capric acid into seal blubber oil.
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Enzyme-assisted Acidolysis of menhaden and seal blubber oils with γ-linolenic acid
Journal of the American Oil Chemists' Society, 2001Co-Authors: Sharon A. Spurvey, S. P. J. Namal Senanayake, Fereidoon ShahidiAbstract:Oils containing both n−3 and n−6 fatty acids have important clinical and nutritional applications. Lipase-catalyzed Acidolysis of seal blubber (SBO) and menhaden oils (MO) with γ-linolenic acid (GLA) was carried out in hexane. The process variables studied for lipase-catalyzed reaction were concentration of enzyme (100–700 units/g of oil), reaction temperature (30–60°C), reaction time (0–48 h), and mole ratio of GLA to triacylglycerols (TAG) (1∶1 to 5∶1). Two lipases chosen for Acidolysis reaction were from Pseudomonas species (PS-30) and Mucor miehei . Lipase PS-30 was chosen over Mucor (also known as Rhizomucor ) miehei to catalyze the Acidolysis reaction owing to higher incorporation of GLA. For the Acidolysis reaction, optimal conditions were a 3∶1 mole ratio of GLA to TAG, reaction temperature of 40°C, reaction time of 24 h, and an enzyme concentration of 500 units/g of oil. Under these conditions, incorporation of GLA was 37.1% for SBO and 39.6% for MO.
Yoshiaki Kiso - One of the best experts on this subject based on the ideXlab platform.
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A Reductive Acidolysis Final Deprotection Strategy in Solid Phase Peptide Synthesis Based on Safety-Catch Protection
Chemical & pharmaceutical bulletin, 1997Co-Authors: Tooru Kimura, Shigeki Tanaka, Toshio Fukui, Kenichi Akaji, Yoshiaki KisoAbstract:A reductive Acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch type of semi-permanent protecting groups and new linkers which were derived from 4-methylsulfinylbenzyl protection. This new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive Acidolysis-cleavable semi-permanent protecting groups. By using this strategy, we successfully synthesized four model peptides, of which two contained C-terminal amide.
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A new reductive Acidolysis final deprotection strategy in solid phase peptide synthesis. Use of a new safety-catch linker
Tetrahedron Letters, 1994Co-Authors: Yoshiaki Kiso, Toshio Fukui, Shigeki Tanaka, Tooru Kimura, Kenichi AkajiAbstract:Abstract A new reductive Acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch linker; this new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive Acidolysis-cleavable semipermanent protecting groups.
Tooru Kimura - One of the best experts on this subject based on the ideXlab platform.
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A Reductive Acidolysis Final Deprotection Strategy in Solid Phase Peptide Synthesis Based on Safety-Catch Protection
Chemical & pharmaceutical bulletin, 1997Co-Authors: Tooru Kimura, Shigeki Tanaka, Toshio Fukui, Kenichi Akaji, Yoshiaki KisoAbstract:A reductive Acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch type of semi-permanent protecting groups and new linkers which were derived from 4-methylsulfinylbenzyl protection. This new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive Acidolysis-cleavable semi-permanent protecting groups. By using this strategy, we successfully synthesized four model peptides, of which two contained C-terminal amide.
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A new reductive Acidolysis final deprotection strategy in solid phase peptide synthesis. Use of a new safety-catch linker
Tetrahedron Letters, 1994Co-Authors: Yoshiaki Kiso, Toshio Fukui, Shigeki Tanaka, Tooru Kimura, Kenichi AkajiAbstract:Abstract A new reductive Acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch linker; this new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive Acidolysis-cleavable semipermanent protecting groups.
Lifeng Peng - One of the best experts on this subject based on the ideXlab platform.
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production of structured phospholipids by lipase catalyzed Acidolysis optimization using response surface methodology
Enzyme and Microbial Technology, 2002Co-Authors: Lifeng Peng, Carlerik Hoy, Jens AdlernissenAbstract:Abstract Structured phospholipids were produced by lipase-catalyzed Acidolysis between soybean phospholipids and free fatty acids. For this purpose three commercially available immobilized lipases were examined and Lipozyme TL IM was finally selected for further optimization. Incorporation of acyl donors, including caprylic acid, conjugated linoleic acid (CLA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), into phospholipids was examined. Different apparent incorporation rates were observed for the individual fatty acids. The main reason was attributed to the purity of the starting acyl donor mixtures, for example the starting material for CLA contained only 77% CLA. The nature of the phospholipids also affected the incorporation rates of caprylic acid catalyzed by Lipozyme TL IM. The following order of reactivity was observed phosphatidylcholine>phosphatidylethanolamine>phosphatidic acid>phosphatidylinositol. Lipozyme TL IM-catalyzed Acidolysis in a solvent-free system was optimized using response surface methodology (RSM). A three-level five-factor fractional factorial design with star points was adopted. The five major factors chosen were lipase dosage ( L d , wt.% based on substrates), water addition ( W c , wt.% based on lipase), reaction time ( T i , h), reaction temperature ( T e , °C), and substrate ratio ( S r , caprylic acid/phospholipids, mol/mol). Acidolysis was influenced by these factors in the following order: T i > L d > S r > T e , whereas water addition had no effect on the incorporation in the range of 2–4 wt.%. The best fitting quadratic model was determined by regression and backward elimination. Based on the fitted model, the optimal reaction conditions for the production of structured phospholipids by Lipozyme TL IM-catalyzed Acidolysis between soybean phospholipids and caprylic acid were found to be T i , 70 h; L d , 30 wt.%; T e , 57 °C, S r , 5.5/1 mol/mol, and no water addition. At these experimental conditions, 39% incorporation of caprylic acid can be obtained.
