Wednesday, January 21, 2009

Utility of Secondary Metabolites

Secondary Metabolism:

Biomolecules such as amino acids, lipids and carbohydrates such as glucose, fatty acids, etc. are involved in the synthesis of various macromolecules such as proteins, nucleic acids, starch and lipids such as triglycerides, steroids, etc. These types of molecules and other related activities such as generation of energy, immunological activities, etc., are essential for the existence of life activities. Such reactions are known as primary metabolism and their products are called primary metabolites. But organisms, when they become mature or when the cells come to the lag phase of growth, operate additional metabolic pathways to synthesize certain compounds, which are not essential for carrying out normal life activities. Such compounds are known as secondary metabolites and their biosynthetic pathway is known as secondary metabolism. Their biosynthesis starts from some primary metabolite or from intermediates of the primary metabolism.

These secondary metabolites are produced in small quantities and are believed not to have any function in the body. But it has been observed that in some cases they have some role in the defense against microorganisms or insects and pests. Even some secondary metabolites are produced in response to the attack of some microorganisms or insects. Some compounds impart special odors to body parts such as flowers or leaves, which attracts or keeps away insects and predators. In plants, there are various types of secondary metabolites such as alkaloids, steroids, terpenes, latex, tannins, resins etc., which are produced and stored in specialized cells, in most cases.

In the case of bacteria and fungus these secondary metabolites are produced at the stationary phase of the growth. Compounds such as antibiotics are the secondary metabolites accumulated by the bacterial cultures and fungus at their stationary phase of growth. The biosynthesis of secondary metabolism is dependent on the state of growth and growth conditions. It is possible to alter the sequence of secondary metabolism by altering growth conditions and media compositions, in the case of bacteria and fungi. Even a change in the pH can alter the route of secondary metabolism in microbial cultures.

Secondary metabolites such as alkaloids, latex, and antibiotics are of great economic value for man. Therefore, these compounds can be synthesized in large quantities by manipulating culture conditions, or by adding the necessary precursors in the media of the cultures.

Tag: Bio Technology, Bio Genetics

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