Abstract
Anthranilate phosphoribosyltransferase (PRT), the second-step enzyme in the tryptophan specific biosynthetic pathway of Brevibacterium flavum, was inhibited by l-tryptophan but not by d-tryptophan, l-phenylalanine or l-tyrosine at all. The pattern of the inhibition by various tryptophan analogs was quite different from that of anthranilate synthase (AS), the first-step enzyme in the pathway. The concentration of trytophan giving 50% inhibition of PRT and the inhibitor constant for tryptophan, Ki, were 0.15 and 0.26 mM, respectively. The inhibition of PRT was noncompetitive for both the substrates, anthranilate and phosphoribosylpyrophosphate. Gycerol increased the sensitivity to the tryptophan inhibition as well as the activity, whereas KCl and NaCl stimulated the PRT activity alone. In all the mutants tested, the feedback inhibition of PRT was removed concomitantly with that of AS. When phenylalanine tyrosine double auxotrophs having derepressed levels of the tryptophan enzymes were cultured under tyrosi...
Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
