The complexity of regulation of ornithine decarboxylase.

Evidence is provided from Escherichia coli, from mammalian cells as well as from germinating barley seeds that there exist positive and negative macromolecular effectors of ODC (ornithine decarboxylase) that modify its activity. These effectors interact with ODC either by forming inactive complexes or by lowering its KmORN resulting in the activation of ODC. These facts, in addition to other evidence presented, argue for the existence of an equilibrium between: (Formula: see text) Such an equilibrium would result in the modulation of ODC activity independently of the net synthesis or degradation of ODC molecules.