GENERAL MICROBIOLOGY - T.P. Pyrog - 2004

20. METABOLIC REGULATION

In the sections addressing microbial METABOLISM, the REGULATION OF METABOLISM and growth by environmental factors was mentioned repeatedly. For instance, the Pasteur Effect (the inhibition of Fermentation by atmospheric oxygen) is a prime example of such regulation. It is also known that certain Enzymes involved in the Catabolism of a specific substrate are synthesized only in its presence (inducible enzymes). In denitrifying Bacteria, nitrate Respiration can commence only in the absence of oxygen, as oxygen inhibits both the formation and function of the nitrate-reducing system. Changes in pH in cultures of Enterobacteriaceae or Clostridia can alter the course of fermentation and influence The Nature of the end products. In phototrophic bacteria, oxygen and light affect pigment synthesis. All of these and other shifts driven by external environmental factors are underpinned by specialized regulatory mechanisms.

Regulation of cellular metabolism can occur at two levels: enzyme synthesis and enzyme activity modulation.



Last update: 12/08/2026

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