Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ester synthesis catalyzed by Candida cylindracea lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) was investigated in solid/liquid biphasic media containing the enzyme preparation and reactants without addition of organic solvents not participating in the reaction. Although the effects of water on enzyme kinetics have been abundantly studied in nearly anhydrous media, reactions in which water is produced have not been investigated. The effect of water produced by the reaction itself on the enzymatic activity was studied. The dispersion of water in a shaken, nearly anhydrous medium was shown to be responsible for the lack of activity of the enzyme. In contrast, when slowly shaken, the enzyme was fully activated by the water furnished as a product of the reaction. However, when experiments were performed in a two-phase aqueous/organic system with previously solubilized enzyme in water, the enzyme activity was increased by shaking and was of the same order of magnitude as in nearly anhydrous media. Under low water activity conditions, a powerful agitation can lead to slower reaction rate, because water, a product of esterification, is not retained in the microenvironment of the enzyme to activate it. The activation effect of water produced by the reaction was clearly shown using enzyme preparations shaken in an anhydrous medium and previously equilibrated at low water activities (aw = 0.13 and 0.69). This activation did not occur for an enzyme preparation equilibrated at high aw (0.89) or for a preparation gently shaken in a water-saturated medium. The lag time preceding activation of the enzyme increased with the extent of enzyme dehydration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Water activity as a key parameter of synthesis reactions: the example of lipase in biphasic (liquid/solid) media. 136 61

The specie Penicillium verrucosum var cyclopium (Westling) has showed that Media containing peptones, especially, trypticase, as a source of nitrogen and maltose or glucose as a source of carbon are most efficient for a good stimulation of the lipolytic activity. Salt, especially Mg++ ion and some oligo- elements exhibit a marked effect on enzyme production. On the other hand, addition of lipids to the growth medium inhibited the lipase production. Shaking of the medium decreases the amount of lipase production but allows an early growth of P. verrucosum var cyclopium (Westling).
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PMID:[Study of the lipolytic system of Penicillium verrucosum var cyclopium (Westling). II. Conditions for the production of the lipase system]. 409 19

Ethanol-oleic acid esterification by a free and microencapsulated lipase from Mucor miehei, using dodecane as solvent and phosphatidylcholine as surfactant, was studied. The initial esterification rate was influenced by the water content in the biphasic system. Kinetic studies with free and microencapsulated enzyme showed that the microencapsulation led to an increase of the kinetic parameters (Vmax and Km), probably due to an increase of the interfacial area. The reaction rate was also affected by the shaking rate, the temperature and the pH. The optimal temperature and pH achieved were, respectively, 40 degrees C and 4.5 using free enzyme, and 50 degrees C and 6 using microencapsulated enzyme.
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PMID:Kinetic studies of Mucor miehei lipase in phosphatidylcholine microemulsions. 776 31

Ashbya gossypii can grow on triacyglycerol as carbon source. A degradation rate of 0.05 g x g-1 mycelial dry mass x h-1 was detected for soybean oil. Although this rate was within the sensitivity range of lipase assays no activity was detectable. On the other hand, extracellular lipase activity could be visualized by clearance halos round the growing mycelium when trioleoylglycerol was emulsified as the sole carbon source in agar plates. Variation of the culture conditions revealed that reduced shaking speed and decreased fat content in the medium led to detectable amounts of lipase in the supernatant of flask cultures. A maximal activity of 800 U x l-1 was obtained after 32 h of cultivation in flasks containing 1% yeast extract and incubated at 60 rpm. Because of its pI of 9.0, the enzyme could be purified in a single step by preparative isoelectric focusing. It appeared as a homogeneous protein in analytical isoelectric focusing and SDS/PAGE (M 35,000). The lipase was inactivated within minutes in stirred gas/water, trioleoylglycerol/water or oleic acid/water mixtures. These effects suggested an interface inactivation. This idea was supported by a stability modulation observed with the surfactant Pluronic F-68. Inactivation by oleic acid led to an aggregation of the lipase shown by gel filtration. Growth experiments performed under lipase-stabilizing conditions revealed a negative influence of glucose, glycerol or oleic acid on detectable lipase activity, probably due to a regulation of lipase formation. Inactivation and regulation thus explained the lack of detectable lipase activity in cultures of A. gossypii growing on triacylglycerol.
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PMID:Regulation and properties of a fungal lipase showing interfacial inactivation by gas bubbles, or droplets of lipid or fatty acid. 906 67

The kinetics of the synthesis of L-ascorbyl laurate and L-ascorbyl palmitate catalysed by immobilized lipase from L-ascorbic acid and an acyl donor (lauric acid, palmic acid and their methyl and ethyl esters) in 2-methylbutan-2-ol have been investigated. The factors affecting the reaction rate (shaking speed, temperature, water activity, enzyme concentration as well as substrate concentration) are discussed. The reaction conditions have been optimized as follows: shaking speed 200 rev./min, temperature 55 degrees C, enzyme 17-20% (w/w of substrate) for these substrates. The most suitable substrate concentration for all of these substrates was 300 mmol/l. The reactions were modelled. For lauric acid, methyl laurate and ethyl laurate: K(m)=74.3, 48.97 and 55.8 mmol/l, respectively; and V(max)=0.010764, 0.0114, 0.01116 mmol.min(-1).g(-1), respectively. The most suitable substrate was methyl laurate. For palmic acid, methyl palmitate and ethyl palmitate: K(m)=102, 94.9 and 104 mmol/l, respectively; and V(max)=0.0417, 0.0424 and 0.0435 mmol.min(-1).g(-1), respectively. The most suitable substrate was methyl palmitate.
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PMID:A kinetic study of the synthesis of ascorbate fatty acid esters catalysed by immobilized lipase in organic media. 1091 36

A lipase-producing bacterium, Acinetobacter calcoacetius LP009, was isolated from raw milk. The optimum conditions for growth and lipase production by A. calcoaceticus LP009 were 15 degrees C with shaking at 200 rpm in LB supplemented with 1.0% (v/v) Tween 80. The crude lipase was purified to homogeneous state by ultrafiltration and gel filtration chromatography on Sephadex G-100. Its molecular weight determined by SDS-PAGE was 23 kDa and it exhibited maximum activity at pH 7.0 and 50 degrees C. It was stable over the pH range of 4.0 to 8.0 and at temperatures lower than 45 degrees C. It was a metalloenzyme that is positionally non-specific and had the ability to improve fat hydrolysis in soybean meal and in premixed animals feed.
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PMID:Purification and characterization of lipase from psychrophilic Acinetobacter calcoaceticus LP009. 1095 Jan 91

We report the first case to our knowledge of chronic pancreatitis associated with mitochondrial encephalopathy with the A8344G mitochondrial DNA (mtDNA) mutation. This 10-year-old-girl had suffered from recurrent abdominal pain with elevated serum amylase and lipase since the age of 6, and easy fatigability, tremor and astatic seizures since the age of 8. A biopsy of quadriceps muscle revealed ragged-red-fibers and cytochrome c oxidase deficiency. Analysis of mtDNA in peripheral blood identified an A8344G mutation in the mitochondrial tRNA(Lys) gene. Taken together with physical signs of myoclonic seizures and cerebellar dysfunction, we diagnosed her as myoclonic epilepsy with ragged-red fibers associated with chronic pancreatitis. Although no association between mitochondrial disease and pancreatitis has yet been established, this case suggests it is necessary to consider the participation of mitochondrial abnormality in the pathogenesis of recurrent pancreatitis.
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PMID:A case of MERRF associated with chronic pancreatitis. 1129 46

Penicillium cyclopium partial acylglycerol lipase production was maximized in shaken batch culture. The effect of inoculum size and substrate concentration on the lipase activity released in the culture medium was visualized using a surface response methodology based on a Doehlert experimental design. The main advantage of this approach is the low number of experiments required to construct a predictive model of the experimental domain. Substrate percentage (corn steep, w/v) ranged from 0.1% to 1.9% and inoculum from 100 spores/ml to 3,200 spores/ml. We determined that an optimal set of experimental conditions for high lipase production was 1.0% substrate and 3,200 spores/ml, with initial pH 5.0, temperature 25 degrees C and shaking speed 120 rpm. Between the conditions giving the minimum and the maximum lipase production, we observed a three-fold increase in both the predicted and the measured values.
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PMID:Maximizing production of Penicillium cyclopium partial acylglycerol lipase. 1246 81

Purified lipase, injected intracerebrally and intravasculariy in rabbits, gave rise to focal areas of demyelinization in the central nervous system in 10 of 13 animals so treated. In one instance the lesions became manifest within 48 hours and in another they persisted for 6 months; they were not infrequently accompanied by paresis and by tilting or tremor of the head. They were characterized by a focal loss of myelin and moderate gliosis with little or no neuronal destruction or inflammatory reaction, in these respects resembling the plaques of multiple sclerosis. The intracerebral injection of trypsin and chymotrypsin in control animals failed to produce the characteristic demyelinization, but by contrast caused focal areas of necrosis in which all the cerebral tissues were involved. Furthermore, demyelinization did not result when heat-inactivated pancreatic lipase was injected intracerebrally, and similarly negative results were obtained when an incubated mixture comprised of fatty connective tissue that had been acted upon by the pancreatic preparation and then heated to inactivate the lipase, was injected into the brains of rabbits. In supplementary experiments the pancreatic lipase preparation and fresh rabbit brain, incubated together in vitro, were found to form acid, presumably owing to the breakdown of brain lipids to fatty acids; trypsin and chymotrypsin mixed with brain in control experiments failed to form acid. When incubated with segments of the spinal cord of experimental animals, the lipolytic enzyme brought about a loss of stainable myelin in peripheral areas and in the spinal nerve roots; again trypsin and chymotrypsin had no such effect in control experiments. The findings as a whole show that an enzyme preparation with lipolytic activity has the ability to destroy myelin in living animals, and in vitro as well, and to produce lesions remarkably similar to those of multiple sclerosis. They have additional interest in light of the demonstration that a lipolytic enzyme is regularly present in the reactive histiocytes of guinea pigs with experimental encephalomyelitis (5).
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PMID:Demyelinization induced in living rabbits by means of a lipolytic enzyme preparation. 1482 2

Ethyl docosahexaenoate (EtDHA) is regarded as a potentially useful pharmaceutical substance on account of its beneficial physiological activities. We attempted the ethyl esterification of docosahexaenoic acid (DHA) in an organic solvent-free system using Candida antarctica lipase, which acts strongly on DHA and ethanol. Esterification of 88% was attained by shaking a mixture of DHA/ethanol (1:1, mol/mol) and 2 wt% immobilized C. antarctica lipase at 30 degrees C for 24 h. However, even in the presence of an excess amount of ethanol, the extent of esterification could not be raised above 90%. To attain a higher level of esterification, a two-step reaction was found to be effective. The first step was performed in a mixture of DHA/ethanol (1:1, mol/mol), and the reaction mixture was then dehydrated. In the second step, the resulting mixture was shaken at 30 degrees C for 24 h with 5 molar equivalents of ethanol against the remaining DHA using 2 wt% immobilized lipase. By means of this two-step procedure, 96% esterification was attained. Repetition of the first and second reactions showed that the immobilized lipase was reusable for at least 50 cycles. In addition, DHA remaining in the second-step reaction mixture was removed by a conventional alkali refining process, giving purified EtDHA with a high yield.
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PMID:Ethyl esterification of docosahexaenoic acid in an organic solvent-free system with immobilized Candida antarctica lipase. 1623 51


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