background l-tryptophan is an important ingredient in medicines, especially in neuromedicines such as antidepressants. many commercial processes employ various microorganisms with high tryptophan synthase activity to produce l-tryptophan from indole and l-serine, but these processes are very costly due to the costs of precursors, especially l-serine. objectives for this reason, we studied the a...

background: l-tryptophan is used widespread in the pharmaceutical industry. the majority of l-trp production depends on microbial processes that produce l-tryptophan from indole and l-serine. these processes are very costly due to the costs of precursors, especially l-serine. use of inexpensive substitutions as the l-serine source of l-tryptophan production enables us to reach a cost-effective ...

background and objectives: the essential amino acid l-tryptophan can be produced by a condensation reaction between indole and l-serine, catalyzed by b. subtilis with tryptophan synthase activity. application of the tryptophan is widespread in the biotechnology domain and is sometimes added to feed products as a food fortifier. materials and methods: the optimum concentration of the iranian can...

L-2-methyltryptophan was prepared from L-serine and 2-methylindole catalyzed by recombinant Escherichia coli with tryptophan synthase activity. In the present research, we used tryptophan synthase (TSase) from recombinant Escherichia coli with pET28a-trpBA plasmid expressing tryptophan synthase from Escherichia coli k-12 MG1655 to produce 2-methyltryptophan, and optimized the conditions for enz...

1. Rat liver tryptophan pyrrolase activity is enhanced by a hormonal-type mechanism during the first 2 days of starvation and by a substrate-type mechanism during the subsequent 2 days. 5-Aminolaevulinate synthase activity is also enhanced during the first 2 days of starvation, but returns thereafter to values resembling those observed in the fed rat. Treatments that prevent or reverse the enha...

A study of the biochemical genetics of the Arabidopsis thaliana tryptophan synthase beta subunit was initiated by characterization of mutants resistant to the inhibitor 5-fluoroindole. Thirteen recessive mutations were recovered that are allelic to trp2-1, a mutation in the more highly expressed of duplicate tryptophan synthase beta subunit genes (TSB1). Ten of these mutations (trp2-2 through t...

The abilities of 14 tryptophan analogs to repress the tryptophan (trp) operon have been studied in Escherichia coli cells derepressed by incubation with 0.25 mM indole-3-propionic acid (IPA). trp operon expression was monitored by measuring the specific activities of anthranilate synthase (EC 4.1.3.27) and the tryptophan synthase (EC 4.2.1.20) beta subunit. Analogs characterized by modification...

............................................................................................................................ 3 INTRODUCTION .................................................................................................................. 4 THE ARMS RACE – BACTERIAL EVOLUTION OF ANTIBIOTIC RESISTANCE ................................. 4 ANTIBIOTIC DRUG DISCOVERY – FROM PENICILLIN...