Enzyme proteins manipulation

Enzymes. Protein engineering has been used both to understand enzyme mechanism and to selectively modify enzyme function (4,5,62—67). Much as in protein stabiUty studies, the role of a particular amino acid can be assessed by replacement of a residue incapable of performing the same function. An understanding of how the enzyme catalyzes a given reaction provides the basis for manipulating the activity or specificity. 

In order to be exploitable for extraction and purification of proteins/enzymes, RMs should exhibit two characteristic features. First, they should be capable of solubilizing proteins selectively. This protein uptake is referred to as forward extraction. Second, they should be able to release these proteins into aqueous phase so that a quantitative recovery of the purified protein can be obtained, which is referred to as back extraction. A schematic representation of protein solubilization in RMs from aqueous phase is shown in Fig. 2. In a number of recent publications, extraction and purification of proteins (both forward and back extraction) has been demonstrated using various reverse micellar systems [44,46-48]. In Table 2, exclusively various enzymes/proteins that are extracted using RMs as well as the stability and conformational studies of various enzymes in RMs are summarized. The studies revealed that the extraction process is generally controlled by various factors such as concentration and type of surfactant, pH and ionic strength of the aqueous phase, concentration and type of CO-surfactants, salts, charge of the protein, temperature, water content, size and shape of reverse micelles, etc. By manipulating these parameters selective sepa-... 

The development of genetically manipulated laboratory mice deficient in or overexpressing enzymes/proteins in the free radical pathways has allowed substantial progress to be made in stroke research. An example is knockout (KO) mice with targeted disruption of the inducible SOD (Mn-SOD or SOD2). The development of these animals has provided a model for studying the effects of free radicals by perturb-... 

Protein manipulation for enzyme proteins can serve as a good example of several possible manipulations. Alteplase is a thrombolysis enzyme protein used to prevent death in acute myocardial infarction. The protein has 527 amino acids, 5 disulfide bridges, glycosylation at several amino acids, and 5 peptide domains. Truncation of most domains leaving intact the protease domain resulted in a new biological, reteplase (Retevase), with quite similar thrombolytic activity. Another set of... 

After a desired clone is obtained and mapped with restriction enzymes, further analysis usually depends on the deterrnination of its nucleotide sequence. The nucleotide sequence of a new gene often provides clues to its function and the stmcture of the gene product. Additionally, the DNA sequence of a gene provides a guidepost for further manipulation of the sequence, for example, lea ding to the production of a recombinant protein in bacteria. 

The biotransformation process has been improved by significant advances in biochemical engineering advances in genetic and protein engineering, microbiological manipulations for the production of enzymes, and the use of biocatalysts in immobilized form and large-scale purification methods. 

In this chapter the roles of various physico-chemical parameters in the interaction between globular proteins, e.g. enzymes, and soil minerals have been discussed semi-quantitatively. Knowledge of the mechanism of that interaction provides a basis to manipulate biological activity in soils. 

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