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The enantioselectivity (E) of lipases in esterifications of secondary alcohols with decanoic acid was studied in organic media. The enantioselectivity of 2-octanol differed greatly among the lipases used. Candida antarctica lipase was extremely selective (E= 9 000) while Candida rugosa lipase was much less selective (E= 1.7). Other enzymes (Lipozyme and lipases from Pseudomonas and Rhizopus arrhiz
The catalytic activities of lyophilized powders of α-chymotrypsin and Candida antarctica lipase were found to increase 4- to 8-fold with increasing amounts of either buffer salts or potassium chloride in the enzyme preparation. Increasing amounts of sorbitol in the chymotrypsin preparation produced a modest increase in activity. The additives are basically thought to serve as immobilization matric
Alcaligenes eutrophus cells containing a soluble NAD-dependent hydrogenase was evaluated as a NADH regenerating catalyst. In the presence of hydrogen and permeabilized A. eutrophus cells, NADH regeneration was achieved, and reductions catalyzed by horse liver alcohol dehydrogenase and lactate dehydrogenase proceeded to 90-99% conversion. The operational stability of the hydrogenase was improved by
The phospholipase A2 (PLA2) catalyzed synthesis and hydrolysis of phosphatidylcholine (PC) was studied in a water activity controlled organic medium. The aim of the study was to find the conditions most favorable for the synthetic reaction. To do this, the impact of various parameters such as water activity, substrate concentration and temperature on enzyme activity and equilibrium yield was deter
Different electron mediators were evaluated for the electromicrobial reduction of chloropyruvate to chlorolactate. The reaction was catalyzed by a mediatol-dependent D-lactate dehydrogenase in whole cells of Proteus vulgaris and yielded D-(S)-chlorolactate with high optical purity (> 97% e.e.). The ideal mediatol should favor a high rate in the enzymatic reaction and a low rate in the nonenzymatic
Diol fatty acid esters find a variety of industrial applications. The use of lipases in microaqueous environment provides an attractive route for synthesis of fatty acyl esters of ethylene glycol. The effect of various process parameters that play key roles in delineating reaction kinetics and distribution of mono- and diesters in the product have been studied.
Immobilized α-chymotrypsin was used as catalyst for studying temperature effects on acyl transfer reactions (acyl-donor: Bz-TyrOEt) in a water-immiscible organic solvent. The solubility of the two nucleophiles, Phe-NH2 and water, decreased with decreasing temperature. The relative decrease for the amide was larger (2.4-fold) than for water. Therefore the thermodynamic activity (estimated by the re
An approach was developed for the isolation and characterization of soybean plasma membrane-associated proteins by immunoscreening of a cDNA expression library. An antiserum was raised against purified plasma membrane vesicles. In a differential screening of approximately 500,000 plaque-forming units with the anti-(plasma membrane) serum and DNA probes derived from highly abundant clones isolated
Den här boken tar ett omfattande grepp om frågor som rör homo, bi, trans, queer och en rad andra identitetskategorier som alla relaterar till sexualitet, relationsbildning, kön och könsuttryck i boken samlade under akronymen hbtq+. Trots en positiv utveckling i samhället leder minoritetsstress fortfarande till ökad ohälsa hos hbtq+-personer, och kunskapsluckorna är stora inom samhälls- och vårdins
The l,3‐ß‐glucan synthase (callose synthase, EC 2.4.1.34) was solubilized from cauliflower (Brassica oleracea L.) plasma membranes with digitonin, and partially purified by ion exchange chromatography and gel filtration [fast protein liquid chromatography (FPLC)] using 3‐[(cholamidopropyl)dimethylammonio]‐1‐propane‐sulfonate (CHAPS) in the elution buffers. These initial steps were necessary to obt
In plants, cells differentiate according to their position with relation to their cell neighbours. Monoclonal antibody (MAb) probes to polysaccharide epitopes, present at the surfaces of all plant cells, have defined a family of proteoglycan antigens which signify cellular position. These MAbs have been used to sort the single cells present in carrot somatic cell cultures on the basis of the prese
