Affiliation:
1. School of Microbiology, University of Melbourne, Parkville, Victoria, Australia
Abstract
The 3-deoxy-
d
-arabinoheptulosonic acid-7-phosphate synthetase which is subject to regulation by tryptophan has been partially purified from a strain of
Escherichia coli
K-12, in which this is the only functional form of this enzyme activity, and from a similar strain possessing a feedback-resistant form of the enzyme. Maximal observed inhibition by tryptophan of the feedback-sensitive enzyme was 56%. There was no evidence for cooperativity in the saturation of the enzyme with tryptophan or E4P. The molecular weights of the feedback-sensitive and feedback-resistant forms of the enzyme were the same (52,000), and no change was detected in the molecular weight of the feedback-sensitve enzyme in the presence of tryptophan. The effect of tryptophan analogues was tested to determine the nature of the tryptophan binding site. Treatment with ethylenediaminetetraacetic acid removed 80% of the activity of the feedback-sensitive enzyme. This activity was restored upon the addition of Co
2+
or Mn
2+
. Neither treatment with ethylenediaminetetraacetic acid nor addition of Co
2+
or Mn
2+
affected the activity of the feedback-resistant enzyme.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference25 articles.
1. The gel filtration behaviour of proteins related to their molecular weights over a wide range;Andrews P.;Biochem. J.,1965
2. Regulation of enzymic activity;Atkinson D. E.;Ann. Rev. Biochem.,1966
3. The synthesis and properties of D-erythrose-4-phosphate;Ballou C. E.;J. Amer. Chem. Soc.,1955
4. End product regulation of the general aromatic pathway in Escherichia coli W;Brown K. D.;Biochim. Biophys. Acta,1963
5. Purification and properties of DAHP synthetase (trp) from E. coli K-12;Camakaris J.;Proc. Aust. Biochem. Soc.,1973
Cited by
23 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献