L-tryptophan transaminase of a bacterium isolated from the rhizosphere of Festuca octoflora (graminae)

  • Frankenberger W
  • poth M
  • 5

    Readers

    Mendeley users who have this article in their library.
  • 32

    Citations

    Citations of this article.

Abstract

Cell-free extracts of a rhizobacterial isolate from Festuca octoflora Walt. contained a soluble α-ketoglutarate-dependent L-tryptophan (L-TRP) transaminase which catalyzes the conversion of L-TRP to indole-3-pyruvic acid (IPyA). The enzyme was purified 35-fold with protamine sulfate and ammonium sulfate (45-65%) precipitation. The IPyA released in the reaction mixture was trapped and partially stabilized as an enol-borate-arsenate complex and measured spectrophotometrically. IPyA production was directly proportional with time (up to 120min) and protein concentration in the ranges employed. The optimum pH and temperature for the catalytic conversion was pH 8.0 and 40°C, respectively. Using L-TRP as the substrate in the presence of α-ketoglutarate (as an amino-group acceptor) and pyridoxal phosphate (as a coenzyme), the average Kmwas 1.22 mM and the activation energy 21.0 kJ mol-1. The role of this enzyme in the microbial synthesis of auxins and its possible influence on plant growth and development are discussed. © 1988.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • W. T. Frankenberger

  • M. poth

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free