Kinetics of induced and repressed enzyme synthesis in Saccharomyces cerevisiae

Our previous work has shown that both induction, after addition of inducer, and loss of ability to produce allophanate hydrolase, after removal of inducer, proceed more rapidly than expected from the reported half-life of messenger ribonucleic acid in Saccharomyces cerevisiae. As a basis of rectifying these observations, we have characterized induction and repression of allophanate hydrolase synthesis and find that: (i) induction of the hydrolase begins immediately upon addition of inducer, (ii) once induction has been initiated removal of inducer does not result in immediate loss of synthetic capacity, (iii) induction of the capacity to produce hydrolase can occur in the absence of protein synthesis, (iv) the half-life of hydrolase synthetic capacity increases if protein synthesis is inhibited, (v) allophanate hydrolase itself is not degraded upon removal of inducer, and (vi) induction and repression of allophanate hydrolase synthetic capacity likely occurs at the level of transcription.