Metabolic Regulation of the Main Metabolism
Pp. 259-290 (32)
Kazuyuki Shimizu and Yu Matsuoka
It is quite important to understand the overall regulation mechanism of a cell
system for the proper modeling. Namely, it is desirable to incorporate how the cell detect
environmental signals, integrate such information, and how the cell system is regulated. In
particular, carbon catabolite regulation (CCR) is of primal importance for the analysis of
overflow metabolism and for the selective assimilation of multiple carbon sources.
Metabolic regulation is made by enzyme level regulation and transcriptional regulation via
the transcription factors. The effects of feed-forward and feed-back regulations on the
metabolism is also explained based on the simple linear system. For CCR, proper
understanding on the phosphotransferase system (PTS) and the transcriptional regulation
by cAMP-Crp and Cra is important. The coordinated regulation between catabolic and
anabolic (nitrogen source-assimilation) metabolism may be made by the keto acid such as
αKG. The effect of oxygen level on the metabolism is explained in terms of global
regulators such as ArcA/B and Fnr. Moreover, the nitrogen regulation in response to
nitrogen limitation is explained. The modeling may be made by taking into account the
metabolic regulation mechanisms of the central metabolism.
Metabolic regulation, catabolite regulation, nitrogen regulation,
transcription factors, Cra, cAMP-Crp, acetate overflow, catabolite repression,
multiple carbon sources, ArcA, Fnr, feed-forward regulation, feed-back
regulation, nitrogen regulation.
Institute of Advanced Biosciences Keio University Tsuruoka Yamagata 997-0017 Japan.