Abstract
The induction, maintenance and activity of tryptophan permease were studied in Escherichia coli T3A, a tryptophan auxotroph which lacks tryptophanase. Under standard conditions, maximum induction requires about Ih and the fully induced system accumulates tryptophan maximally in about 60 sec. The maintenance and induction concentrations of tryptophan are identical. The accumulation system is repressed by low temperatures and by glucose, and is more sensitive to chloramphenicol synthesis-inhibition than is gross cellular growth. The concentration-dependent accumulation of tryptophan conforms to Michaelis-Menton kinetics and exhibits a pronounced temperature dependence. The half-maximal accumulation, loss and exchange times at several temperatures and in several ambients suggest a separation of the processes of accumulation (retention), entry and exit. Under the conditions tested, tryptophan permease appears to confer no growth advantage on E. coli .
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
