H 2 ‐Driven Flavin Recycling Supports Biocatalytic Halogenation by Flavin‐Dependent Halogenase

Journal article

We report a simplified, H2‐driven method for operating biocatalytic halogenation by a flavin‐dependent halogenase, PyrH, which enables intensification of biocatalytic conversion of L‐tryptophan to its 5‐halo product. Flavin‐dependent halogenases are gaining traction in biotechnology as their substrate scope is expanded by enzyme discovery and engineering, but their application remains impeded by a particularly complex electron transfer chain and the fact that full conversion is generally only achieved at sub‐millimolar substrate concentrations. Here, we apply nickel‐iron hydrogenase and ambient pressure H2 in place of the NAD(P)+, glucose, glucose dehydrogenase and reductase which are normally used to supply reduced FAD to halogenases. Together with controlled delivery of O2, which is needed for generating a hypohalous acid intermediate, we achieve full conversion of 5.5 mM tryptophan, with a PyrH total turnover number of 275, and PyrH turnover frequency of 0.76 min−1 over a 6 h reaction, comparable with rates sustained only for short reaction times using the conventional glucose‐driven system. This should help to facilitate application of flavin‐dependent halogenases in fine chemical synthesis.

Authors: Peng, J; Ramirez, MA; Vincent, KA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: ChemCatChem
• Article number: e01548
• Publication date: 2025-12-10
• Acceptance date: 2025-11-21
• DOI: 10.1002/cctc.202501548
• EISSN: 1867-3899
• ISSN: 1867-3880
• Language: English
• Keywords: Flavin recycling; Flavin‐dependent halogenase; Biocatalysis; Hydrogenase; Halogenation