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81.
《Biocatalysis and Biotransformation》2013,31(2):114-122
AbstractThe aim of this study was to model the lipase-catalyzed esterification of policosanols with conjugated linoleic acid (CLA) in a solvent-free system to produce wax esters which had a lower melting point than that of their corresponding policosanol forms and to optimize the reaction conditions by response surface methodology (RSM). Novozym 435 was selected as a suitable biocatalyst for the reaction. The molar ratio of substrates (policosanols to CLA) was 1:2. A well-fitting quadratic polynomial regression model for the degree of esterification (DE) of policosanols with CLA was established with regard to temperature (35–65°C), enzyme loading (1–5% of weight of total substrates), and reaction time (10–50 min). Optimal reaction conditions were 61.3°C for temperature, 3.7% for enzyme loading, and 34.1 min for reaction time, and the DE was ? 95 mol% under these conditions. The policosanols and wax esters synthesized under optimal conditions had melting points of 79°C and 57°C, respectively. 相似文献
82.
Cathepsins L and B are lysosomal cysteine proteinases whose activities and cellular location are altered in many types of cancers and cancer cell lines. Cathepsins L and B play an unspecified role in cancer invasion and metastasis. The purpose of our study was to determine whether cathepsins L and B are important for the ability of two prostate cancer cell lines, PC3 and DU 145, to invade the basement membrane-like preparation, Matrigel®. Exposure of PC3 and DU145 to the irreversible cysteine proteinase inhibitor, E64, decreases the invasive ability of DU145, but not PC3. PC3 and DU145 were treated with the phorbol ester analogue, phorbol 12-myristate 13-acetate (PMA), a known tumor promoter that activates protein kinase C and contributes to the metastatic phenotype. PMA increased secreted cathepsin L+B activity and the invasive ability of PC3 and DU145; co-exposure to E64 and PMA decreased both cathepsin L+B activity and invasion. We conclude that DU145 requires cathepsin L+B activity more than PC3 for the invasion of the Matrigel®. When the amount of secreted cathepsin L+B activity is increased by PMA treatment, however, PC3 becomes dependent on cathepsin L+B for invasion. Our study demonstrates that modulation of the amount of secreted cathepsin L+B activity influences the invasive phenotype of PC3 and DU145. 相似文献
83.
《Biotechnic & histochemistry》2013,88(6):297-304
Germinating and growing pollen grains (male gametophytes) of Ricinus communis L. in liquid culture is achieved as follows: Pollen is collected over a 10-15 min period from mature anther clusters which have been removed from the male flowers and which have been kept at 25° C and 40-60% relative humidity. Samples weighing between 2.5 and 5.0 mg are brought as quickly as possible into a Desicote treated vial containing 17% sucrose and 30 ppm H3BO3 in boiled distilled water. The proportion (w/v) of pollen to culture solution should be 1:100. Shed pollen is kept in a humidity chamber whenever it is not being handled. The air in the culture vial is replaced by O2 at the pressure of 1 atmosphere plus 5 lb and the sealed vials are shaken gently for 8-10 hr while partially immersed in a waterbath kept at 30° C. The pollen is fixed by the addition to the incubation suspension of an absolute alcohol-lactic acid (4:1) fixing fluid. The proportion used is 36 parts of fixing fluid to 1 part of culture solution. The fixed pollen can be stored in the fixative. Smears are prepared by applying single drops of the constantly agitated suspension of fixed pollen to a microscope slide. After each drop has spread out and dried, an additional drop is added until 10-20 have been applied. The preparations are stained by adding a drop of 1% acetic-orcein and are sealed with fingernail lacquer. The method is well adapted to the following types of studies: pollen germination, physiology of pollen tube growth, morphology of the male gametocyte, and physiology and cytology of the generative cell and nucleus. 相似文献
84.
85.
Methodology for the rapid N‐acylation of aminothiols in aqueous solution using procedures commonly employed in biochemical studies is described here. Glutathione disulfide (GSSG) and homocystine were diN‐acetylated in ~100% yield in 0.1 M aqueous NaHCO3 (pH 8.5) at room temperature by 2.5 equiv of the activated ester, N‐hydroxysulfosuccinimidyl acetate, an efficient water‐soluble acetylating reagent. Following acetone precipitation, diN‐acetylGSSG was further purified and desalted on a strong anion‐exchange (SAX) cartridge. DiN‐acetylhomocystine was simultaneously purified and desalted on a C18 cartridge. The N‐acetylated aminothiols were generated using gel‐immobilized tris(2‐carboxyethyl)phosphine as a reductant, which obviated the need for further purification. Alternatively, disulfide exchange with dissolved dithiothreitol yielded N‐acetylglutathione, which was purified on the SAX cartridge. pH titrations of N‐acetylglutathione (8.99) and N‐acetylhomocysteine (9.66) as well as those of commercially available N‐acetylcysteine (9.53) and N‐acetylpenicillamine (10.21) yielded pKa(SH) values of importance for biological studies. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
86.
Natarajan Suganthy Shanmugiahthevar Karutha Pandian 《Journal of enzyme inhibition and medicinal chemistry》2013,28(3):702-707
Alzheimer's disease is a progressive neurodegenerative illness accounting for approximately 50% of all types of dementia in elderly people. The only symptomatic treatment proven effective to date is the use of cholinesterase inhibitors to augment surviving cholinergic activity. The purpose of this study is to investigate cholinesterase inhibitory activity of mangroves as an alternative medicine for the treatment of Alzheimer's disease. About nine mangrove plants, which were used as folk medicine in tropical countries, were collected from Parangipettai, Vellar estuary, Tamilnadu, India. Nile Tilapia muscle homogenate was used as source of enzyme. Inhibitory effect of methanolic leaf extract was assessed under in vitro condition by incubating various concentration of the extract with total cholinesterase and butyryl cholinesterase and assessing their residual activities by Ellman's colorimetric method. The results showed that of the nine plants screened Rhizophora lamarckii, Suaeda monica, Avicennia officinalis and Sesuvium portulacastrum showed 50% inhibitory activity to both TChE and BChE at concentrations less than 2 mg/mL when compared to other plant extracts, which was comparable to the standard drug Donepezil. Phytochemical analysis showed the presence of alkaloids in high concentration which might be correlated to its cholinesterase inhibitory activity. 相似文献
87.
Saied Ghadimi Ali Asghar Ebrahimi Valmoozi Mehrdad Pourayoubi Keyvan Asad Samani 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):556-561
Phosphoramido acid esters (CH3)2NP(O)X(p-OC6H4-CH3) (containing P-Cl (1), P-O (2), P-F (3), P-CN (5), and P-N (4,6) bonds, X for 2, 4 and 6 is OCH3, (C2H5)2N and morpholin) have been synthesized to investigate the structure-activity study of AChE enzyme inhibition, through the parameters logP, δ31P and IC50. After their characterization by 31P, 31P{1H}, 13C, 1H NMR, IR and mass spectroscopy, the parameters logP and δ31P (31P chemical shift in NMR) were used to evaluated the lipophilicity and electronical properties. The ability of compounds to inhibit human AChE was predicted by PASS software (version 1.193), and experimentally evaluated by a modified Ellman's assay. 相似文献
88.
β-amino acids are widely used in drug research, and S-3-amino-3-phenylpropionic acid (S-APA) is an important pharmaceutical intermediate of S-dapoxetine, which has been approved for the treatment of premature ejaculation. Chiral catalysis is an excellent method for the preparation of enantiopure compounds. In this study, we used (±)-ethyl-3-amino-3-phenylpropanoate (EAP) as the sole carbon source. Three hundred thirty one microorganisms were isolated from 30 soil samples, and 17 strains could produce S-APA. After three rounds of cultivation and identification, the strain Y1-6 exhibiting the highest enantioselective activity of S-APA was identified as Methylobacterium oryzae. The optimal medium composition contained methanol (2.5 g/L), 1,2-propanediol (7.5 g/L), soluble starch (2.5 g/L), and peptone (10 g/L); it was shaken at 220 rpm for 4–5 days at 30 °C. The optimum condition for biotransformation of EAP involved cultivation at 37 °C for 48 h with 120 mg of wet cells and 0.64 mg of EAP in 1 ml of transfer solution. Under this condition, substrate ee was 92.1% and yield was 48.6%. We then attempted to use Methylobacterium Y1-6 to catalyze the hydrolytic reaction with substrates containing 3-amino-3-phenyl-propanoate ester, N-substituted-β-ethyl-3-amino-3-phenyl-propanoate, and γ-lactam. It was found that 5 compounds with ester bonds could be stereoselectively hydrolyzed to S-acid, and 2 compounds with γ-lactam bonds could be stereoselectively hydrolyzed to (-)-γ-lactam. 相似文献
89.
Seongah Han Lauretta LeVoci Paul Fischer Sheng-Ping Wang Karen Gagen Ying Chen Dan Xie Timothy Fisher Anka G. Ehrhardt Andrea M. Peier Douglas G. Johns 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(4):825-833
Cholesteryl ester transfer protein (CETP) is a target of therapeutic intervention for coronary heart disease. Anacetrapib, a potent inhibitor of CETP, has been shown to reduce LDL-cholesterol by 40% and increase HDL-cholesterol by 140% in patients, and is currently being evaluated in a phase III cardiovascular outcomes trial. HDL is known to possess anti-inflammatory properties, however with such large increases in HDL-cholesterol, it is unclear whether CETP inhibition perturbs HDL functionality such as anti-inflammatory effects on endothelial cells. The purpose of the present study was to determine whether CETP inhibition by anacetrapib affects the anti-inflammatory properties of HDL. HDL was isolated from either hamsters treated with vehicle or anacetrapib for 2 weeks, or from normal human subjects treated either placebo, 20 mg, or 150 mg anacetrapib daily for 2 weeks. Anacetrapib treatment increased plasma HDL cholesterol levels by 65% and between 48 and 82% in hamsters and humans, respectively. Pre-incubation of human aortic endothelial cells with HDL isolated from both control and anacetrapib treated hamsters suppressed TNFα induced expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin. Similar results were obtained with human HDL samples pre and post treatment with placebo or anacetrapib. Further, HDL inhibited TNFα-induced MCP-1 secretion, monocyte adhesion and NF-κB activation in endothelial cells, and the inhibition was similar between control and anacetrapib treated groups. These studies demonstrate that anacetrapib treatment does not impair the ability of HDL to suppress an inflammatory response in endothelial cells. 相似文献
90.