Future Developments

We may assume that current trends will continue. As the number of gene sequences continues to expand, with the completion of the human genome project not far off, not to mention the many other genomes being sequenced, there will be more demand to ex press and purify these gene products. In many cases the actual nature of the protein will be unknown, with no assay available. By having a reliable fusion system, as outlined above, gene products can be isolated without knowing what their biological function is. So the use of standard affinity materials will be a major item in protein purifications in the near future. But there will still be a need for the more personal affinity system, for studying and isolating components of protein-protein or protein-DNA interactions. For this, the researcher needs a reliable activated matrix (such as those that have been commercially available for many years), to which to add the protein or DNA and get instant attachment.

Table 2 A selection of affinity tagging systems available commercially. Most tags are placed at the N-terminus of the expressing protein, but some, notably the hexahistidine, can be placed at either end

System: fusion protein

Affinity adsorbent

Size offusion (kDa)

Hexahistidine

Immobilized metal: Ni or Co

1-2

Glutathione S-transferase

Glutathione

26

Maltose-binding protein

Amylose

38

Cellulose-binding domain

Cellulose

35

T7 Polymerase (peptide)

Monoclonal antibody

1

Protein A (partial)

IgG

14

Biotinylation site

Streptavidin

1

Various epitopes

Monoclonal antibodies

1 #

See also: I/Affinity Separation. II/Affinity Separation:

Affinity Membranes; Affinity Partitioning in Aqueous Two-Phase Systems; Aqueous Two-Phase Systems; Biochemical Engineering Aspects; Covalent Chromatography; Dye Ligands; Hydrophobic Interaction Chromatography; Immobilized Boronates and Lectins; Immobilized Metal Ion Chromatography; Immunoaffinity Chromatography; Imprint Polymers; Rational Design, Synthesis and Evaluation: Affinity Ligands. Appendix 1/Essential Guides for Isolation/Purification of Enzymes and Proteins. Essential Guides for Isolation/ Purification of Immunoglobulins. Appendix 2/Essential Guides to Method Development in Affinity Chromatograhy.

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Solar Panel Basics

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