Glucocorticoid hormones increase the level of hepatic tryptophan oxygenase (EC 1.13.11.11; L-tryptophan:oxygen 2,3-oxidoreductase (decyclizing) by increasing its rate of synthesis. Studies were performed to determine whether this induction is mediated by controlling the level of the mRNA for tryptophan oxygenase of by changing the translational efficiency of a fixed level of mRNA. Activity of t...

Genes are involved in eating disorders (EDs) and self-induced vomiting (SV), a key symptom of different types of EDs. Perfectionism and impulsivity are potential risk factors for EDs. TPH2 (tryptophan hydroxylase 2) SNP rs1473473 was previously associated with anorexia nervosa and EDs characterized by SV. Could perfectionism or impulsivity be underlying the association between rs1473473 and EDs...

L-Tryptophan-2,3-dioxygenases (EC 1.13.1.12), purified to homogeneity from Pseudomonas acidovorans and from rat liver, have been shown to contain as bound cofactors, 2 g atoms copper and 2 moles of heme per mole of tetrameric enzyme. Kinetic and spectral studies, utilizing the metal complexing agents diethyldithiocarbamate (Cu2+ specific), bathocuproinesulfonate (Cu+ specific), and bathophenant...

A year ago, in this journal, Zhang and coworkers (Zhang et al., 2005) reported that the gene encoding the enzyme responsible for the synthesis of brain sero-tonin, tryptophan hydroxylase-2 (THP2), exhibited a functional variant associated with major (or unipolar) depression. The variant in question (G1463A) altered a critical amino acid (Arg441His) in the enzyme such that, at least in a transfe...

The signalling molecule indole occurs in significant amounts in the mammalian intestinal tract and regulates diverse microbial processes, including bacterial motility, biofilm formation, antibiotic resistance and host cell invasion. In Escherichia coli, the enzyme tryptophanase (TnaA) produces indole from tryptophan, but it is not clear what determines how much indole E. coli can produce and ex...

Expression of the tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. In a previous study, we reproduced the regulatory features of this operon observed in vivo by using an in vitro S-30 system. We also found that, under inducing conditions, the leader peptidyl-tRNA (TnaC-peptidyl-tRNA(Pro)) is not cleaved; i...