EC 1.14.19.60     
Accepted name: 7-chloro-L-tryptophan 6-halogenase
Reaction: 7-chloro-L-tryptophan + FADH2 + chloride + O2 + H+ = 6,7-dichloro-L-tryptophan + FAD + 2 H2O
Other name(s): ktzR (gene name)
Systematic name: 7-chloro-L-tryptophan:FADH2 oxidoreductase (6-halogenating)
Comments: An FAD-dependent halogenase. The enzyme, characterized from the bacterium Kutzneria sp. 744, works in tandem with EC 1.14.19.9, tryptophan 7-halogenase, (ktzQ) to generate 6,7-dichloro-L-tryptophan, which is incorporated as a pyrroloindoline in the kutznerides family of natural products. It has a 120-fold preference for 7-chloro-L-tryptophan over L-tryptophan as substrate.
References:
1.  Heemstra, J.R., Jr. and Walsh, C.T. Tandem action of the O2- and FADH2-dependent halogenases KtzQ and KtzR produce 6,7-dichlorotryptophan for kutzneride assembly. J. Am. Chem. Soc. 130 (2008) 14024–14025. [PMID: 18828589]
[EC 1.14.19.60 created 2018]