1,721,032 research outputs found
Control of the reaction media characteristics on the biocatalytic activity of microbial lipases
No full textConformational aspects of a "very simple" chain: polyacetylene
No full textPotential energy calcns. of the isolated chains of trans- [25768-71-2] and cis-polyacetylene [25768-70-1] were made to obtain information on the most probable conformations. Previously reported different sets of van der Waals potential functions, different values for the of barrier height to bond rotation, and different geometries for the repeating unit were used. Calcns. were also made of the 7-atom chains of polyacetylene for which independent rotations were allowed around three consecutive quasi-single bonds. The deepest min. on the potential energy map of the trans 3-atom chain were consistent with the all-trans conformation (the most stable one) and with a distorted cis conformation, which deviated from planarity because of the repulsion between H atoms 1 and 4. The energy maps of the cis polymer showed two min., both of which corresponded to nonplanar conformations. From the 7-atom chain anal. of both polymers, in addn. to stable conformations obtained for the 3-atom chains, other min. corresponded to triplets formed from both conformers
Macrolide antibiotic intermediate preparation through Pseudomonas cepacia lipase biocatalyzed reactions
No full textA lipase form Pseudomonas sp. has been employed as enantioselective catalyst in transesterification reaction using a substrate bicyclo[2.2.1]heptene derivatives and acetic esters with different substitution in organic moieties in organic solvent. The influence of hte chemical structure of the acyl donors has been studied
Modulazione dell'attività catalitica di lipasi: uso di solventi ed anticorpi monoclonali
No full textFrom organic solvents to supercritical fluids and ionic liquids: the role of the medium in the applied biocatalysis
No full textWe have been working in different applications of lipases from different sources, wild and mutated, with different classes of organic solvents and different model substrates, trying to establish some correlations between physico-chemical characteristics of the solvents and structural aspects of the substrate. More recently, room-temperature ionic liquids have been also employed as media for biocatalysed reactions. Besides potential environmental benefits, ionic liquids permit enzyme-catalysed reactions in a solvent polarity range that was previously inaccessible, offering major advantages with polar substrates
Enzymatic preparation of chiral intermediates for macrolide antibiotics
No full textA Pseudomonas sp. lipase has been employed as enantioselective catalyst in transesterification reactions using as substrates bicyclo[2.2.1]heptene derivatives and acetic esters in organic solvents. The influence of the reaction medium on the activity and enantioselectivity of the lipase in transesterification reactions was investigated
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