Protein recombinant, problems

Second, it has not been possible to isolate and purify cellulose synthases from higher plants and so it has been difficult to prepare antibodies against this protein. This problem was overcome by expressing a fragment of the cotton CesA cDNA that encoded the catalytic region of a cotton cellulose synthase in E. coli and using the recombinant protein for obtaining polyclonal antibodies. 

Whole cells are grown for a variety of reasons. The cells may perform a desired transformation of the substrate, e.g., wastewater treatment the cells themselves may be the desired produce, e.g., yeast production or the cells may produce a desired product, e.g., penicillin. In the later case, the desired product may be excreted, as for the penicillin example, and recovered in relatively simple fashion. If the desired product is retained within the cell walls, it is necessary to lyse (rupture) the cells and recover the product from a complex mixture of cellular proteins. This approach is often needed for therapeutic proteins that are created by recombinant DNA technology. The resulting separation problem is one of the more challenging aspects of biochemical engineering. However, culture of the cells can be quite difficult experimentally and is even more demanding theoretically. 

The previous ELP fusions all are examples of protein purification in which the ELP is covalently connected to the protein of choice. This approach is suitable for the purification of recombinant proteins that are expressed to high levels, but at very low concentrations of ELP the recovery becomes limited. Therefore this approach is not applicable for proteins expressed at micrograms per liter of bacterial culture, such as toxic proteins and complex multidomain proteins. An adjusted variant of ITC was designed to solve this problem. This variant makes use of coaggregation of free ELPs with ELP fusion proteins. In this coaggregation process, an excess of free ELP is added to a cell lysate to induce the phase transition at low concentrations of... 

Cell-free translation system, used for the identification of cloned genes and gene expression, has been investigated extensively as a preparative production system of commercially interesting proteins after the development of continuous-flow cell-free translation system. Many efforts have been devoted to improve the productivity of cell-free system [1], but the relatively low productivity of cell-free translation system still limits its potential as an alternative to the protein production using recombinant cells. One approach to enhance the translational efficiency is to use a condensed cell-free translation extract. However, simple addition of a condensed extract to a continuous-flow cell-free system equipped with an ultrafiltration membrane can cause fouling. Therefore, it needs to be developed a selective condensation of cell-free extract for the improvement of translational efficiency without fouling problem. 

If immune reactions are to be avoided then recombinant human factor should be used and that cannot be produced in large quantities. In any case, it is a large protein that will have to be injected directly into the brain. Even if these problems can be overcome the spread and intensity of any NGF effect has to be restricted so that excessive neuritic growth and inappropriate increases in synaptic connections do not occur. 

A final problem for bioinformatics and bioanalytical scientists is the characterization of engineered microorganisms. Whole-cell analysis by mass spectrometry has been used to confirm the introduction of therapeutic genes into adenovirus vectors,100 to confirm the expression of recombinant proteins in bacteria,101,102 and also in vaccinology.103 In the broader case, identification of... 

Looking at the downstream processing of recombinant pharmaceutical proteins from different sources as a whole, there are more common steps than operations addressing expression system-specific problems or requirements. One of the most important common features is that a given end product must meet the same standards and specifications in terms of safety, quality, potency and efficacy, regardless of the production host. Furthermore, the physicochemical properties of such end products should be identical, so that the intrinsic features used for purification (affinity, hy-drophobicity etc.) are the same. Well-established procedures and protocols should therefore be utilized, and should be adapted to the special requirements of the source material only when absolutely necessary. This is particularly true in the case of pharmaceuticals, since the tendency in this field is to stick to established methods... 

It overcomes the problem of source availability. Many proteins of therapeutic potential are produced naturally in the body in minute quantities. Examples include interferons (Chapter 8), interleukins (Chapter 9) and colony-stimulating factors (CSFs Chapter 10). This rendered impractical their direct extraction from native source material in quantities sufficient to meet likely clinical demand. Recombinant production (Chapters 3 and 5) allows the manufacture of any protein in whatever quantity it is required. 

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