|
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 |
Activity |
4.1.99.1 |
Family |
4.1.99.1 |
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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