Subtilisin 72 suspension retained high activity and stability in the triple mixtures acetonitrile/DMF/water (DMF concentration was up to 70% (v/v)). The synthetic activity of subtilisin suspension ...was investigated using the model reaction of tetrapeptide Z-Ala-Ala-Leu-Phe-
pNA formation from Z-Ala-Ala-Leu-OMe and Phe-
pNA (S=30
mM, E=6
μM; S/E molar ratio 5000:1). In the systems containing up to 60% DMF the 95% product yield was reached within 2
h. With DMF concentration increasing to 95%, the subtilisin catalytic efficiency notably decreased, though the product yield was still 30%. In the mixture acetonitrile/80%DMF/water, the effects of enzyme concentration, the reaction time and water content on the reaction progress were studied.
A recombinant adenovirus was generated with the human Ï1 GABA C receptor subunit (adeno-Ï). Patch-clamp and antibody staining were employed to confirm functional expression of recombinant
Ï1 ...receptors after infection of human embryonic kidney cells (HEK293 cell line), human embryonic retinal cells (911 cell line),
dissociated rat hippocampal neurons and cultured rat hippocampal slices.
Standard whole-cell recording and Western blot analysis using Ï1 GABA C receptor antibodies revealed that recombinant Ï1 receptors were expressed in HEK293 and 911 cells after adeno-Ï infection
and exhibited properties similar to those of Ï1 receptors after standard transfection.
Cultured rat hippocampal neurons (postnatal day (P)3-P5) did not show a native GABA C -like current. After adeno-Ï infection, however, a GABA C -like current appeared in 70-90 % of the neurons.
Five days after infection, expression of GABA C receptors in hippocampal neurons significantly decreased native GABA A receptor currents from 1200 ± 300 to 150 ± 70 pA ( n = 10). The native glutamate-activated current was unchanged.
Hippocampal slices (P8) did not show a native GABA C -like current, although recombinant Ï1 receptors could be expressed in cultured hippocampal slices after adeno-Ï infection.
These data indicate that an adenovirus can be used to express recombinant GABA C receptors in hippocampal neurons. This finding could represent an important step towards the gene therapy of CNS receptor-related
diseases.
New water-soluble macromolecular palladium complexes with phase transfer ability were used for two-phase Wacker oxidation of higher alkenes. Macromolecular metal complexes have been prepared ...employing as ligands monobutyl ether of polyethylene oxide and copolymers of ethylene oxide and propylene oxide functionalized by β,β'-iminodipropionitrile and acetodinitrile. Macromolecular metal complexes exhibited high activity and selectivity as catalysts for Wacker oxidation of different alkenes: octene-1, dodecene-1, hexadecene-1, styrene, propenylbenzene, cyclooctadiene-1,5. The complexes based on β,β'-iminodipropionitrile ligands showed the highest activity. All catalysts can be easily separated from product and used repeatedly without decrease of activity.
An enzymatic synthesis of tripeptide Z-Ala-Ala-Leu-pNA, tetrapeptides Z-Ala-Ala-P
1-P
1′-Xaa, where P
1 = Leu, Trp, Met, Ala, Ile, Phe; P
1′ =Phe, Ala, Leu; Xaa = pNA, NH
2, pentapeptides ...Z-Ala-Ala-Leu-Ala-Ala-pNA and Z-Ala-Ala-Leu-Ala-Phe-pNA is described. The reactions were performed in organic solvents using SDS-subtilisin complex as a catalyst of the peptide bond synthesis.
Noncovalent subtilisin-sodium dodecyl sulfate complex dissolved in ethanol and 2-propanol catalyzes the peptide bond formation, for example, (pNA -
p - nitroanilide):
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