Recombinant expression

On the protein level, transient expression allows feasibility studies to be conducted rapidly, as it enables production of limited amounts of protein for first analysis within weeks. 

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Mehrishi JN, Szabo M, Bakacs T (2007) Some aspects of the recombinantly expressed humanised superagonist anti-CD28 mAb, TGN1412 trial catastrophe lessons to safeguard mAbs and vaccine trials. Vaccine 25 3517-3523... 

In particular, the availability of such bacterial biocatalysts in the form of recombinant expression systems [136] in combination with simplified purification protocols opened up this methodology for large-scale applications [204]. 

Keeley, F.W., Bellingham, C.M., and Woodhouse, K.A., Elastin as a self-organising biomaterial Use of recombinantly expressed human elastin polypeptides as a model system for investigations of structure and self-assembly of elastin, Philos. Trans. R. Soc. Lond. B Biol. Sci., 357, 185-189, 2002. 

One way to relate the concentration of an intermediate to other concentrations is by assuming that earlier reversible steps have equal forward and reverse rates. The proposed mechanism begins with the decomposition of Bf2 molecules into Br atoms, most of which recombine rapidly to give Br2 molecules. At first, Br2 molecules decompose faster than Br atoms recombine, but the Br atom concentration quickly becomes large enough for recombination to occur at the same rate as decomposition. When the two rates are equal, so are their rate Rate of decomposition = Rate of recombination expressions Rr2] =. 1 [Br] ... 

Most biochemical and biocatalytic studies have been performed with type I B VMOs. This is partly because of the fact that they represent relatively uncomplicated monooxygenase systems. These monooxygenases are typically soluble and composed of only one polypeptide chain. Expression systems have been developed for a number of type I BVMOs while no recombinant expression has been reported for a type II BVMO. Cyclohexanone monooxygenase (CHMO) from an Acinetobacter sp. NCIMB9871 was the only recombinant available BVMO... 

Manya, H., et al. (2000). Comparative study of the asparagine-linked sugar chains of human lipocalin-type prostaglandin D synthase purified from urine and amniotic fluid, and recombinantly expressed in Chinese hamster ovary cells. 

A thermally stable NHase from Comamonas testosteroni 5-MGAM-4D (ATCC 55 744) [22] was recombinantly expressed in Escherichia coli, and the resulting transformant cells immobilized in alginate beads that were subsequently chemically cross-linked with glutaraldehyde and polyethylenimine. This immobilized cell catalyst (at 0.5 % dew per reaction volume) was added to an aqueous reaction mixture containing 32wt% 3-cyanopyridine at 25 °C, and a quantitative conversion to nicotinamide was obtained. The versatility of this catalyst system was further illustrated by a systematic study of substrates, which included... 

The recombinantly expressed nitrilase from Pseudomonas fluorescens EBC 191 (PFNLase) was applied in a study aimed at understanding the selectivity for amide versus acid formation from a series of substituted 2-phenylacetonitriles, including a-methyl, a-chloro, a-hydroxy and a-acetoxy derivatives. Amide formation increased when the a-substituent was electron deficient and was also affected by chirality of the a- stereogenic center for example, 2-chloro-2-phenylacetonitrile afforded 89% amide while mandelonitrile afforded 11% amide from the (R)-enantiomer but 55% amide was formed from the (5)-enantiomer. Relative amounts of amide and carboxylic acid was also subject to pH and temperature effects [87,88]. 

Based on the above principles, it might be assumed that a therapeutic protein obtained by direct extraction from human sources (e.g. some antibody preparations) or produced via recombinant expression of a human gene/cDNA sequence (e.g. recombinant human hormones or cytokines) would be non-immunogenic in humans whereas foreign therapeutic proteins (e.g. non-engineered monoclonal antibodies) would stimulate a human immune response. This general principle holds in many cases, but not all. So why do therapeutic proteins of human amino acid sequences have the potential to trigger an immune response Potential reasons can include ... 

Here, we describe the various alternatives to the use of E. coli expression hosts for heterologous gene expression. Advantages and disadvantages for the different expression systems are discussed, and practical aspects of expression technologies are also described. The feasibility of isotope labeling of recombinantly expressed proteins and their potential use for NMR is also discussed, since the costs and quantities of recombinant proteins produced depend on the system being used. 

Procedure 1 Recombinant Expression of the BVMO from P. fluorescens DSM 50106 in E. coli... 

Axen E, Postlind H, Sjoberg H, Wikvall K. 1994. Liver mitochondrial cytochrome P450 CYP27 and recombinant-expressed human CYP27 catalyze 1 alpha-hydroxylation... 

Once the recombinant expression vectors containing the cDNA inserts are produced, they are used to transform bacteria (or other host cells) and produce cDNA (expression) libraries. Expression libraries may be used to produce recombinant proteins that in some cases have significant advantages over isolating them from natural sources ... 

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