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B6db references: 8534987

type Journal Article
authors Kawasaki K, Yokota A, Tomita F.
title Enzymatic synthesis of L-tryptophan by Enterobacter aerogenes tryptophanase highly expressed in Escherichia coli, and some properties of the purified enzyme
journal Biosci Biotechnol Biochem
sel selected
ui 8534987
year (1995)
volume 59
number 10
pages 1938-43
keywords Amino Acid Sequence
abstract We constructed two plasmids that have a strong tac promoter and a structural gene for tryptophanase of Enterobacter aerogenes SM-18 (pKT901EA) or Escherichia coli K-12 (pKT951EC). The tryptophanase activity of E. coli JM109 transformed with pKT901EA (JM109/pKT901EA) was inducible with isopropyl-beta-D-thiogalactopyranoside, and 3.6 times higher than that of E. aerogenes SM-18. Cells of JM109/pKT901EA induced for tryptophanase synthesized L-tryptophan from indole, ammonia, and pyruvate more efficiently than E. aerogenes SM-18. Although JM109/pKT951EC expressed a similar level of tryptophanase activity to that of JM109/pKT901EA, the synthesis of L-tryptophan by the cells of JM109/pKT951EC did not proceed well compared with JM109/pKT901EA. Tryptophanases from E. aerogenes and E. coli K-12 were purified, and their properties were investigated. The purified E. aerogenes tryptophanase showed higher stability against heat inactivation than E. coli tryptophanase.
last changed 2008/01/22 18:06

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