Biological functional properties advantage

Cells contain thousands of different proteins. A major problem for protein chemists is to purify a chosen protein so that they can study its specific properties in the absence of other proteins. Proteins have been separated and purified on the basis of their two prominent physical properties size and electrical charge. A more direct approach is to employ affinity purification strategies that take advantage of the biological function or similar specific recognition properties of a protein (see Table 5.5 and Chapter Appendix). 

It is evident that aldehyde-containing saponins, particularly those from Quillaja saponaria Molina, have unique features which provide them with particular immune stimulating properties. However, some of their chemical properties cause instability and toxicity which interfere with their utility as adjuvants. A better understanding of the underlying relationships between the saponin s chemical structure and biological functions, such as immune system modulation and toxicity, would allow the future development of semi-synthetic and synthetic molecules having the advantages but not the liabilities of these natural products. 

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