Search results for "Specificity."

ChemInform Abstract: Total Synthesis of (+)-Greek Tobacco Lactone.

2015

An enantioselective, protecting-group-free, total synthesis of (+)-Greek tobacco lactone has been achieved by using an organocatalytic Mukaiyama–Michael reaction and a stereospecific oxa-Michael reaction as key steps.

Total Synthesis of (+)-Greek Tobacco Lactone

2014

An enantioselective, protecting-group-free, total synthesis of (+)-Greek tobacco lactone has been achieved by using an organocatalytic Mukaiyama–Michael reaction and a stereospecific oxa-Michael reaction as key steps.

Analysis of odour and taste problems in high-density polyethene

1998

Abstract The compounds that cause off-flavours in plastics, have been recognized mainly as carbonyl compounds (aldehydes, ketones and esters). They occur in low concentrations, and due to their low-threshold odour concentrations, their typical odours were identified. Most of these off-flavour compounds are volatile. Chemical analysis of smelling compounds requires a very sensitive method with a high-resolution capability. The analysis of volatile organic compounds (VOCs) in high density polyethene (HD-PE) granules and waters in which the granules have been shaken for 4 h, were carried out by gas chromatography–mass spectrometry–sniffing system (GC–MS–SNIFF) and by gas chromatography–fourier…

The influence of α-aminophosphonic acids on the activity of aminopeptidase from barley seeds—an approach to determine the enzyme specificity

2015

Inhibitory potencies of 24 α-aminophosphonic acids against barley seeds (Hordeum vulgare L.) metallo-aminopeptidase have been determined to evaluate structural requirements of this enzyme. The enzyme was sensitive mostly to the influence of phosphonic acid analogues of phenylalanine and its homologues, thus showing narrow specificity if compared with porcine aminopeptidases M1 and M17 and with Plasmodium aminopeptidase M17.

Study of a lipase from Candida rugosa Diddens and Lodder

1993

Lipasic system of Candida rugosa (CBS 613) strain was studied. The enzyme was purified in one step by hydrophobic chromatography. The properties of this lipase were determined. It is an oligomeric enzyme composed of five identical monomers of 46 kg · mol−1. Its optimum reaction conditions are pH = 7 and temperature = 40°C. This enzyme presents a rapid thermal denaturation and then a more stable form. It is a cell-bound lipase which is induced by triacyl glycerols. This enzyme presents a high specificity for external positions on glycerol. Unterschung einer Lipase aus Candida rugosa Diddens und Lodder Die Reinigung einer Lipase aus Candida rugosa (CBS 613) wurde in einer einzigen Stufe durch…

Differential behaviour of Pseudomonas sp. 42A2 LipC, a lipase showing greater versatility than its counterpart LipA

2009

Abstract Growth of Pseudomonas sp. 42A2 on oleic acid releases polymerized hydroxy-fatty acids as a result of several enzymatic conversions that could involve one or more lipases. To test this hypothesis, the lipolytic system of strain Pseudomonas sp. 42A2 was analyzed, revealing the presence of at least an intracellular carboxylesterase and a secreted lipase. Consensus primers derived from a conserved region of bacterial lipase subfamilies I.1 and I.2 allowed isolation of two secreted lipase genes, lipA and lipC, highly homologous to those of Pseudomonas aeruginosa PAO1. Homologous cloning of the isolated lipA and lipC genes was performed in Pseudomonas sp. 42A2 for LipA and LipC over-expr…

Trapping of Different Lipase Conformers in Water-Restricted Environments

1996

Based on a recently reported strategy to rationally activate lipolytic enzymes for use in nonaqueous media [Mingarro, I., et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 3308-3312], we compared the behavior in water-restricted environments of activated vs nonactivated forms of different lipases toward their natural substrates, triacylglycerols. To this end, nine lipases from varied origins (mammalian, fungal, and bacterial) were assayed using simple acidolyses as nonaqueous model reactions. The experimental results for several (though not all) lipases, discussed in the light of current structural and functional information, were collectively consistent with a model where, depending on the "…

Chemistry of Enzyme Visualization

1994

The basic principle of enzyme visualization in situ is to present an enzyme with a solution containing an enzyme specific substrate. Demonstration of an enzyme is achieved if the catalytic action of the enzyme on this substrate produces a coloured reaction product. Often, however, the primary reaction products are colourless and require coupling with a visualizing agent to generate a coloured, preferably insoluble, final reaction product.

Mechanism of stereospecific polymerization of styrene with alkali metal alkyls

2007

Dataset relative to article "Sensitivity and specificity of a commercial ELISA test for anti-MAG antibodies in patients with neuropathy"

2021

This record contains data related to article “Sensitivity and specificity of a commercial ELISA test for anti-MAG antibodies in patients with neuropathy". Abstract For the diagnosis of anti-MAG polyneuropathy the commercial ELISA manufacturer currently recommends a cut-off of 1000 Bühlmann Titer Units (BTU). We analyzed sera from 80 anti-MAG neuropathy patients and 383 controls (with other neuropathies or healthy controls) to assess the ELISA sensitivity and specificity at different thresholds. A better combination of sensitivity/specificity was found at a threshold >1500 BTU than at >1000 BTU. The best value of specificity was obtained at threshold >7000 BTU. There…