These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: 3-Deoxy-D-arabino-heptulosonate 7-phosphate synthase. Purification and molecular characterization of the phenylalanine-sensitive isoenzyme from Escherichia coli.
    Author: McCandliss RJ, Poling MD, Herrmann KM.
    Journal: J Biol Chem; 1978 Jun 25; 253(12):4259-65. PubMed ID: 26682.
    Abstract:
    The phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (7-phospho-2-keto-3-deoxy-D-arabino-heptonate D-erythrose-4-phosphate lyase (pyruvate phosphorylating), EC 4.2.1.15) was purified to apparent homogeneity from extracts of Escherichia coli K12. The enzyme has a molecular weight of 140,000 as judged by gel filtration and sedimentation equilibrium analysis. The enzyme has a subunit molecular weight of 35,000 as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, suggesting that the native form of the enzyme is a tetramer. This was confirmed by cross-linking the enzyme with dimethylsuberimidate and by analyzing the cross-linked material by gel electrophoresis in the presence of sodium dodecyl sulfate. The enzyme shows a narrow pH optimum between pH 6.5 and 7.0. The enzyme is stable for several months when stored at -20 degrees C in buffers containing phosphoenolpyruvate. Removal of phosphoenolpyruvate causes an irreversible inactivation of the enzyme. The enzyme is strongly inhibited by L-phenylalanine and to a lesser degree by dihydrophenylalanine. Molecular parameters of the previously isolated tyrosine-sensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase from E. coli (Schoner, R., and Herrmann, K.M. (1976) J. Biol. Chem. 251, 5440-5447) are compared with those of the phenylalanine-sensitive isoenzyme from the same organism.
    [Abstract] [Full Text] [Related] [New Search]