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1.
N-vanillylnonanamide (VAN) was successfully synthesized from vanillylamine hydrochloride by enzymatic catalysis in supercritical carbon dioxide (SC–CO2). Five commercial lipases, Novozyme 435, Lipozyme IM, Amano PS, Amano G and Sigma Candida cylindracea type VII, as biocatalysts for VAN synthesis were compared. Lipozyme IM exhibited best yields of tested lipases. Various parameters such as time, temperature, pressure and vanillylamine hydrochloride/nonanoic anhydride ratio that influenced the reaction were investigated. Nonanoic anhydride showed the best acyl donor of the employed substrates. An amidation yield of 40% was obtained when nonanoic anhydride and Lipozyme IM were used at 170 bar and 50 °C for 23 h in SC–CO2. Besides, addition of 2 mM divalent salts (CuCl2 and ZnCl2) significantly increased 11–23% yield of the VAN. The enzyme operational stability suggested that Lipozyme IM maintained over 50 °C of the initial activity for the synthesis of VAN after reuse for 69 h. Furthermore, in vitro, VAN behaved as a potential antibacterial against Escherichia coli. 相似文献
2.
Hiroyuki Kawashima Tomomi Kuruma Masayuki Yamashita Youhei Sohma Kenichi Akaji 《Journal of peptide science》2014,20(5):361-365
O‐Acyl isopeptides, in which the N‐acyl linkage on the hydroxyamino acid residue (e.g. Ser and Thr) is replaced by an O‐acyl linkage, generally suppress unfavorable aggregation properties derived from the corresponding parent peptides. Here, we report the synthesis of an O‐acyl isopeptide of 34‐mer pyroGlu‐ADan (2), a component of amyloid deposits in hereditary familial Danish dementia, by using native chemical ligation. Native chemical ligation of pyroGlu1‐ADan(1‐21)‐SCH2CH2SO3?Na+ (3) and Cys22‐O‐acyl isopeptide (4), in which the amino group of the Ser29 residue at the isopeptide moiety was protected by an allyloxycarbonyl group, proceeded well in an aqueous solvent to yield a ligated O‐acyl isopeptide (5). Subsequent disulfide bond formation and deprotection of the allyloxycarbonyl group followed by HPLC purification gave 2 with a reasonable overall yield. 2 was converted to the parent peptide 1 via an O‐to‐N acyl migration reaction. The sequential method, namely (i) native chemical ligation of the O‐acyl isopeptide, (ii) HPLC purification as the O‐acyl isopeptide form, and (iii) O‐to‐N acyl migration into the desired polypeptide, would be helpful to solve problems with HPLC purification of hydrophobic polypeptides in the process of chemical protein synthesis. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
3.
(2R)-2-[4-(4-Cyano-2-fluorophenoxy)phenoxy]butylpropanoate (cyhalofop-butyl, CyB) was synthesized by a chemoenzymatic route involving
enantioselective transesterification with Candida antarctica lipase B (Novozym 435). The optimum organic solvent, acyl donor, a
w
, reaction temperature and shaking rate for the transesterification were acetonitrile, n-butanol, 0.11, 45°C and 200 rpm, respectively. Under the optimum conditions, the maximum substrate conversion and the enantiomeric
purity of the product were 96.9 and >99%, respectively. The total yield and enantiomeric purity of CyB by this chemoenzymatic
synthesis were 60.4 and >99%, respectively; 15.3 and 21% higher than that of the traditional way (45 and 78%). 相似文献
4.
《Redox report : communications in free radical research》2013,18(3):116-125
AbstractObjectivesPlant-derived natural substances, such as capsaicin, with potent antiproliferative activity against cancer cells in vitro are considered to be promising nutraceuticals in anticancer therapy. Nevertheless, the limited systemic bioavailability of phytochemicals may raise questions regarding the physiological relevance of their phytochemical effects in vivo. Thus, the search for novel phytochemical-based substances with more efficient anticancer action is needed.MethodsIn the present study, a capsaicin analogue, namely, capsaicin epoxide, was synthesized, and its cytotoxic potential against cancer cells was evaluated and compared to that of capsaicin through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and multi-caspase assays. The abilities of capsaicin and capsaicin epoxide to induce oxidative stress were estimated using redox-sensitive fluorogenic probes: 2′,7′-dichlorodihydrofluorescein diacetate (H2DCF-DA) and dihydroethidium.ResultsThe structure and purity of the synthesized product were confirmed by nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry, and gas chromatography. Normal human dermal fibroblasts were not susceptible to treatment with the agent, whereas a cancer cell type-specific response was observed. Human breast carcinoma cells were found to be the most sensitive to capsaicin epoxide treatment compared with capsaicin treatment, and the action of capsaicin epoxide was oxidant based.DiscussionOur data indicate that the antiproliferative activity of capsaicin epoxide is potentiated in vitro, when used at much lower concentrations compared with capsaicin at similar concentrations. Thus, the findings of this study may have implications for phytochemical-based anticancer drug development. 相似文献
5.
Mikio Fujii Sadayuki Ishii Ryota Saito Hiroyuki Akita 《Journal of Molecular Catalysis .B, Enzymatic》2009,59(4):254-260
The optical resolution of racemic albicanol (rac-1) based on the lipase-catalyzed transesterification by using vinyl myristate as an acyl donor afforded (8aR)-1 (99% ee) in 43% yield and (8aS)-1 (99% ee) in 37%. E value of the enzymatic reaction was 56.7 which was superior to that of the reported value (E = 25) by using isopropenyl acetate as an acyl donor. As the synthetic application of obtained (8aR)-1, (−)-copalic acid ((8aR)-3) and (−)-copalol ((8aR)-4) were synthesized from (8aR)-1 in 35% and 34% total yield, respectively. 相似文献
6.
A novel strategy for a more efficient synthesis of difficult sequence‐containing peptides, the S‐acyl isopeptide method, was developed and successfully applied. A model pentapeptide Ac–Val–Val–Cys–Val–Val–NH2 was synthesized via its water‐soluble S‐acyl isopeptide using an S‐acyl isodipeptide unit, Boc–Cys(Fmoc–Val)–OH. An S‐acyl isopeptide possessing excellent water solubility could be readily and quantitatively converted to the native peptide via an S N intramolecular acyl migration reaction at pH 7.4. Thus, the S‐acyl isopeptide method provides a useful tool in peptide chemistry. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
7.
Aryl acylamidase (EC 3.5.1.13, AAA) acts on the amide bond between aryl and acyl groups. Whole cells of Escherichia coli overexpressing a novel bacterial AAA synthesized p-acetaminophenol (p-AAP) from p-aminophenol (p-AP, aryl compound) and acetate (acyl donor). Optimum conditions were pH 5.5 and 35°C with 100 mM p-AP and 600 mM sodium acetate in 100 mM sodium phosphate buffer including 1% (v/v) Triton X-100 for 60 h. 13.1 g p-AAP l−1 was produced with a conversion yield of 87%. 相似文献
8.
Microsomal preparations from developing linseed (Linum usitatissimum L.) cotyledons catalyzed i) acyl exchange between acyl-CoA and position 2 of sn-phosphatidylcholine, ii) acylation of sn-glycerol 3-phosphate to yield phosphatidic acid, and iii) the utilisation of phosphatidic acid in the production of diacylglycerol and triacylglycerol. Selectivity studies for C18 acyl species of acyl-CoA indicated a bias for the channelling of oleate to phosphatidylcholine for, presumably, its desaturation, and the utilisation of the polyunsaturated fatty-acid products in the acyl-CoA pool for phosphatidic acid and subsequent triacylglycerol synthesis. The microsomal preparations were capable of returning glycerol backbone with associated acyl components to phosphatidylcholine from diacylglycerol where it may be further enriched with polyunsaturated C18 acids by desaturation. The acyl quality in linolenate-rich oilseeds appears to be under similar control to that found in linoleate-rich species.
Present address: To whom the correspondence should be addressed 相似文献
9.
An alkyl ether analog of phosphatidylcholine was synthesized and used as a ligand to purify acid-extracted phospholipase A2 from bovine ileum smooth muscle by affinity chromatography in the presence of cholate. This ligand contains a primary amino group at the ω-position of the acyl chain in position 1 and so permits direct covalent coupling with the ester group of Affi-Gel-10. An endogenous membrane bound phospholipase A2 has been purified 32-fold in a good yield (70%) employing this ligand in an affinity chromatography step. 相似文献
10.
The ability of Streptococcus thermophilus ST1 and 19 other dairy lactic acid bacteria (LAB) to synthesize esters was investigated in an aqueous environment. These LAB were able to synthesize esters from alcohols and glycerides via a transferase reaction (alcoholysis) in which fatty acyl groups from glycerides were transferred to alcohols. S. thermophilus ST1 was active on tributyrin and on di- or monoglycerides of up to C10 with ethanol as the acyl acceptor. This strain was also active on a diglyceride of C6 and monoglyceride of C8 with 2-phenyl ethanol as the acyl acceptor. Alcoholysis occurred preferentially over hydrolysis. S. thermophilus ST1 had an apparent Km value of 250 mM for ethanol and an apparent Km value of 1.3 mM for tributyrin, measured against whole cells. Around 80% of both the transferase activity and the esterase activity were detected in the cell-free extract (CFE) of strain ST1. Both activities in the CFEs of five LAB tested were, to a similar degree, enhanced slightly by growth in the presence of ethanol and tributyrin. Using tributyrin and ethanol as substrates, the transferase activities ranged over 0.006–1.37 units/mg cell dry weight among the LAB tested and were both species- and strain-dependent. 相似文献
11.
Danping Qi Wei Wei Mingming Diao Fengxia Lv Zhaoxin Lu Xiaomei Bie 《Biocatalysis and Biotransformation》2016,34(5):194-204
Lipase-catalyzed synthesis of mono- and diesters of 3-O-β-D-galactopyranosyl-sn- glycerol (β-GG) with caproic acid was performed in acetone. The simultaneous production of 1(6’)-monoesters and 1,6’-diesters of β-GG was achieved in this reaction. In order to improve the yield of β-GG esters, four process parameters, enzyme concentration (15?~?25?mg/mL), and substrate molar ratio (caproic acid: β-GG=?1.60?~?2.00?mmol: 0.10?mmol), reaction temperature (40?~?60?°C), and reaction time (8?~?12?h), were optimized via response surface methodology (RSM) employing a three-level-four-variable central composite design. Results showed that enzyme concentration had the most significant (p?0.0001) effect on the synthesis of β-GG esters. The optimal reaction conditions in acetone were given as follows: Novozyme435 concentration 18.65?mg/mL, molar rate of caproic acid to β-GG 19.46:1, reaction temperature 48?°C, and reaction time 9.83?h. The yield of β-GG esters reached 88.08% under above optimized conditions, which was very close to the predicted value 87.95%. The molar ratio of monoester to diesters was 0.39:0.61. β-GG esters with other fatty acyl chains were synthesized based on the optimized conditions. In vitro antitumor activity indicated that the antitumor activity of β-GG esters was dependent on the nature of fatty acids, such as the length of acyl chain, the degree of saturation, as well as the number of acyl chain. 相似文献
12.
Kenji Kobata Mamiko Kobayashi Yukiyoshi Tamura Shozo Miyoshi Susumu Ogawa Tatsuo Watanabe 《Biotechnology letters》1999,21(6):547-550
Transacylation of capsaicin with triolein using a commercial lipase gave olvanil in an 85% yield at 70°C for 144 h. When olive oil was employed, the major product was olvanil (62%). Safflower oil gave a mixture of olvanil (39%) and linoleoyl vanillylamide (32%). Perilla oil gave linolenoyl vanillylamide (13%). Myristic acid and its methyl ester could be used as an acyl donor, and myristoyl vanillylamide was obtained in 20–78% using several lipases. 相似文献
13.
The crucial step in the preparation of the title arsonolipids starting from the dichloromethane-soluble dithioarsonite CH2(OH)CH(OH)CH2–As(SPh)2 is to avoid an internal cyclization during the acylation which protects the primary –OH group from being acylated. This was to a large extent accomplished by using fatty acyl chloride in the presence of the weak base pyridine and controlling the temperature and rate of the acyl chloride addition, giving ~70% yields of arsonolipids. The presence of catalytic amounts of 4-dimethylaminopyridine boosted the yields to 82–85%. This yield is a great improvement over the yields (20–55%) previously achieved. The acylating systems (RCO)2O or RCOCl and BF3·Et2O gave only moderate yields (25–60%) of arsonolipids. 相似文献
14.
Keisuke Kitamura Kazuyoshi Okubo Kazuo Shibasaki 《Bioscience, biotechnology, and biochemistry》2013,77(5):1083-1085
Kinetics of the acyl transfer catalyzed by Xanthomonas α-amino acid ester hydrolase was studied. The enzyme hydrolyzed d-α-phenylglycine methyl ester (d-PG-OMe) to give equimolar amounts of d-α-phenylglycine and methanol. With d-PG-OMe as an acyl donor and 7-amino-3-deacetoxy-cephalosporanic acid (7-ADCA) as an acyl acceptor, the enzyme transferred the acyl group from d-PG-OMe to 7-ADCA in competition with water. The addition of amine nucleophiles (7-ADCA and 6-aminopenicillanic acid) decreased the molecular activity (ko) of the enzyme-catalyzed hydrolysis of d-PG-OMe, whereas it did not alter the Michaelis constant (KM), and plots of l/ko against the initial concentration of a nucleophile (no) gave a straight line. These results support the assumptions that the overall process for hydrolysis and acyl transfer proceeds through a common acyl-enzyme intermediate, that the acylation step of the enzyme is rate-limiting, and that the transfer competes with the hydrolysis of the acyl donor. 相似文献
15.
Silke Deerberg Johanna von Twickel Hans-Heinrich Förster Thomas Cole Jochen Fuhrmann Klaus-Peter Heise 《Planta》1990,180(3):440-444
During their rapid maturation period, seeds of Cuphea wrightii A. Gray mainly accumulate medium-chain fatty acids (C8 to C14) in their storage lipids. The rate of lipid deposition (40–50 mg·d–1·(g fresh weight)–1) is fourfold higher than in seeds of Cuphea racemosa (L. f.) Spreng, which accumulate long-chain fatty acids (C16 to C18). Measurements of the key enzymes of fatty-acid synthesis in cell-free extracts of seeds of different maturities from Cuphea wrightii show that malonyl-CoA synthesis may be a triggering factor for the observed high capacity for fatty-acid synthesis. Experiments on the incorporation of [1-14C]acetate into fatty acids by purified plastid preparations from embryos of Cuphea wrightii have demonstrated that the biosynthesis of medium-chain fatty acids (C8 to C14) is localized in the plastid. Thus, in the presence of cofactors for lipid synthesis (ATP, NADPH, NADH, acyl carrier protein, and sn-glycerol-3-phosphate), purified plastid fractions predominantly synthesized free fatty acids, 30% of which were of medium chain length. Transesterification of the freshly synthesized fatty acids to coenzyme A and recombination with the microsomal fraction of the embryo homogenate induced triacylglycerol synthesis. It also stimulated fatty-acid synthesis by a factor 2–3 and increased the relative amount of medium-chain fatty acids bound to triacylglycerols, which corresponded to about 60–80% in this lipid fraction.Abbreviations ACP
acyl carrier protein
- FW
fresh weight
This work was supported by the Bundesminister für Forschung und Technologie. The authors thank S. Borchert for her suggestions for plastid preparation. 相似文献
16.
《Process Biochemistry》2010,45(12):1888-1893
The lipase of Rhizopus oryzae (R. oryzae) was reported to have 1(3)-positional specificity, but in the process of R. oryzae-catalyzed biodiesel production, the yield of biodiesel (methyl esters) could reach over 80%. Although during 1(3)-positional specific lipase-catalyzed methanolysis of triglycerides, acyl migration was thought as one of the major reasons for higher methyl ester yield, there was no further study on the mechanism exploration regarding to acyl migration. In this paper, acyl migration and the related kinetics of R. oryzae-mediated methanolysis of triolein was studied systematically. Through our study, it was revealed that during the methanolysis process, acyl migration between 2-MG and 1-MG as well as acyl migration between 1,2-DG and 1,3-DG could take place independent of enzymatic catalysis. The kinetic study showed that the acyl migration was first-order reversible reaction. Based on this finding, a two-step mechanic model including acyl migration was developed for the enzyme-mediated methanolysis for biodiesel production and it was found that the reaction included consecutive hydrolysis and esterification. Further investigation on kinetics showed that R. oryzae lipase was not restrict selectivity of 1(3)-position acyl group, but a preference of 1(3)-position over 2-position, which also contributed to the higher yield of methyl esters. 相似文献
17.
J. R. Hazel N. P. Neas 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1982,149(1):11-18
Summary Rainbow trout (Salmo gairdneri) acclimated to 5°C or 20°C were administered 2-3H-glycerol and 1-14C-acetate (63 Ci of each isotope/100 g body weight) via intraperitoneal injection, and subsequently maintained at their respective acclimation temperatures. Total lipid extracts (>80% phospholipid) were prepared from isolated microsomes of liver, gill and muscle tissue at various times over a three week period. Half-lives were determined independently for the fatty acyl and glycerol moieties from slopes of regression lines relating dpm/nmole phospholipidP
i vs time. In liver tissue, rates of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) turnover were also determined. Membrane turnover was most rapid in liver followed by gill and muscle. In liver, membrane fatty acids turned over more rapidly in warm-(t
1/2=3.4 days) than in cold-(t
1/2=6.8 days) acclimated fish, whereas in gill, rates of fatty acid turnover, did not differ significantly between acclimation groups. In contrast, rates of glycerol turnover were independent of acclimation temperature in liver, but faster (t
1/2=6.7 days) in warm- than cold- (t
1/2=15.1 days) acclimated fish in gill. In total lipid extracts, rates of fatty acid and glycerol turnover were equivalent in warm-acclimated fish, however, in cold-acclimated trout, there was a tendency for fatty acids (t
1/2=9.1 days) to turnover more rapidly than glycerol (t
1/2=15.1 days) in gill tissue, but more slowly (t
1/2=6.82 days) than glycerol (t
1/2=4.1 days) in liver. Although rates of glycerol turnover were equivalent in PC and PE of liver microsomes, the fatty acyl component turned over significantly more rapidly in PC at both acclimation temperatures. In cold-acclimated trout, rates of fatty acid and glycerol turnover were equivalent in PE, but the fatty acyl moiety of PC (t
1/2=4.7 days) turned over significantly more rapidly than glycerol (t
1/2=7.5 days). These results were interpreted as indicating that: (1) acclimation temperature independently influenced rates of fatty acid and glycerol turnover in a tissue specific manner, (2) a deacylation-reacylation pathway was activated in both liver and gill as a consequence of cold acclimation, but that liver tissue was more effective than gill in reutilizing the fatty acids released by phospholipase activity, and (3), in liver microsomes, patterns of turnover were phospholipid specific, with PC and PE differing either in the susceptibility of their acyl groups to degradation, or in their ability to reutilize fatty acids cleaved during membrane turnover at cold temperatures. 相似文献
18.
《International journal of biological macromolecules》1986,8(3):153-156
O-Nitratedchitosan (d.s. 1.5–1.8 for NO2 was N-acylated with carboxylic anhydride to afford products (d.s. 1.4–1.8 for NO2 in 78–100% yield, and N-acylchitosan (d.s. 1.0 for N-acyl was nitrated with fuming nitric acid-acetic anhydride to afford products (d.s. 1.7–2.0 for NO2 in 90–100% yield. N-Benzoylchitosan was nitrated with fuming nitric acid-acetic anhydride to afford a product of d.s. 3.0 for NO2. All the products were soluble in methanesulphonic acid. The nitrated products containing N-fatty acyl groups (> C2) were soluble in N, N-dimethylformamide and dimethyl sulphoxide, but the nitrated products containing N-fatty acyl groups (> C6) were insoluble or swelled. O-Nitrated chitosan (d.s. 1.5–1.8 for NO2) had ignition points 150–1562C, but the nitrated products containing N-acyl groups had no ignition point, and decomposed at over 2402C. 相似文献
19.
Summary. The capability of ficin, a cystine protease, to form peptide bonds was investigated using several types of N-Boc-amino acid phenyl and naphthyl esters as acyl donor components. Enzyme-catalyzed peptide synthesis was carried out under
optimized reaction conditions of pH, acyl acceptor concentration and selection of the best yield organic solvent. It used
a condensation of N-Boc-Ala-OpGu and Ala-pNA as a model reaction. The products were obtained in 72–96% yield using 10 different substrates, within a few minutes of
reaction time.
Authors’ address: Prof. Haruo Sekizaki, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu,
Hokkaido 061-0293, Japan 相似文献
20.
Seiichi Nonomura Ryotaro Kotani Rintaro Urakabe Shoji Shima Heiichi Sakai 《Bioscience, biotechnology, and biochemistry》2013,77(9):1755-1756
A series of partially and heterogeneously N-acylated chitosans was prepared and isolated in 50 ~ 100% yields. The structure of N-acyl groups influenced the gelation. The minimum requirement for the gelation was defined as ca. 0.4 N-lauroyl (C12), ca. 0.6 N-fatty acyl (C3–C10) or ca. 0.7 N-benzoyl groups per hexosaminide residue. However, the gelation did not occur with N-high fatty acyl (C14-C18) groups.1) 相似文献