[Changes in enzyme activities during the growth of cell suspension cultures ofGlycine max: Phenylalanine ammonia-lyase and p-coumarate: CoA ligase].

1. A typical growth curve including a lag phase, phases of cell division and cell expansion and a stationary phase could be demonstrated for batch propagated cells ofGlycine max. in synthetic liquid medium. 2. Shortly before the stationary phase was reached, dramatic changes in the activities of two enzymes of "secondary plant metabolism", phenylalanine ammonia-lyase and p-coumarate: CoA ligase, were observed. In contrast, the activity of acetate:CoA ligase remained constant during this period of time, indicating that primary cell metabolism was unaffected. 3. Activities of both enzymes, phenylalanine ammonia-lyase and p-coumarate: CoA ligase, could be enhanced by light. Using disc gel electrophoresis it was not possible to detect isoenzymes of phenylalanine ammonia-lyase in extracts either from cells grown in the dark or from those treated with light.