FADH2-Dependence of Tryptophan 7-Halogenase

Tryptophan 7‐halogenase (Trp 7‐hal) catalyses the regioselective chlorination and bromination of tryptophan. For halogenating activity, Trp 7‐hal requires FADH2 produced from FAD and NADH by a flavin reductase, halide ions (chloride or bromide), molecular oxygen and tryptophan as the organic substra...

Full description

Saved in:
Bibliographic Details
Published in:Advanced synthesis & catalysis 2005-06, Vol.347 (7-8), p.1163-1167
Main Authors: Unversucht, Susanne, Hollmann, Frank, Schmid, Andreas, van Pée, Karl-Heinz
Format: Article
Language:English
Subjects:
enzymatic halogenation
FADH2 regeneration
flavoenzyme
monooxygenase
organometallic catalyst
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Tryptophan 7‐halogenase (Trp 7‐hal) catalyses the regioselective chlorination and bromination of tryptophan. For halogenating activity, Trp 7‐hal requires FADH2 produced from FAD and NADH by a flavin reductase, halide ions (chloride or bromide), molecular oxygen and tryptophan as the organic substrate. Investigations of the flavin dependence showed that purified Trp 7‐hal itself does not contain flavin. Keeping the Trp 7‐hal separated from the flavin reductase during the reaction revealed that Trp 7‐hal can use diffusible FADH2 produced by a flavin reductase showing that direct contact between the halogenase and the flavin reductase is not absolutely necessary. Thus, the reaction also proceeds when chemically reduced flavin is used. For the catalytic regeneration of FADH2, the organometallic complex (pentamethylcyclopentadienyl)rhodium‐bipyridine {[Cp*Rh(bpy)(H2O)]2+} can be employed as the redox catalyst with formate as the electron donor. With this chemoenzymatic system about 85% yields of the product formed by the two‐component enzyme system consisting of Trp 7‐hal and a flavin reductase were obtained.
ISSN:1615-4150
1615-4169
DOI:10.1002/adsc.200505029