Specific enzymatic chlorination of tryptophan and tryptophan derivatives.
In the search for an alternative to chemical halogenation reactions using the free halogens, a novel type of halogenating enzymes was detected. In contrast to haloperoxidases, these NADH-dependent halogenases are specific. Tryptophan halogenase which catalyses the regioselective chlorination of tryptophan to 7-chlorotryptophan can also chlorinate tryptamine, tryptophol, indole-3-acetonitrile, and 3-methylindole. However, indole-3-acetonitrile is not chlorinated in the 7-position, but in positions two and three of the indole ring. Chlorination in the 3-position is obviously stereospecific. In addition to tryptophan and indole derivatives, aminophenylpyrrole is also accepted as a substrate for regioselective chlorination. Since the new NADH-dependent halogenases have a fairly broad substrate specificity and catalyse regioselective chlorination reactions they could be a good alternative to chemical halogenation.
van Pée
K H
KH
Technische Universität Dresden, Institut für Biochemie, Germany. Karl-Heinz.vanPee@chemie.tu-dresden.de
Hölzer
M
M
D006219:Halogens / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D013379:Substrate Specificity; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000378:metabolism*
D006219:Halogens; D009243:NAD; D014364:Tryptophan; D010088:Oxidoreductases; C407364:monodechloroaminopyrrolnitrin halogenase; C407363:tryptophan halogenase; D010544:Peroxidases