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Library of Norcoclaurine Synthases and Their Immobilization for Biocatalytic Transformations
Author(s) -
Lechner Horst,
Soriano Pablo,
Poschner Roman,
Hailes Helen C.,
Ward John M.,
Kroutil Wolfgang
Publication year - 2018
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201700542
Subject(s) - chemistry , biocatalysis , computational biology , biochemistry , nanotechnology , combinatorial chemistry , biology , materials science , catalysis , reaction mechanism
Norcoclaurine synthases (NCS), catalyzing a Pictet–Spengler reaction in plants as one of the first enzymes in the biosynthetic benzylisoquinoline pathway, are investigated for biocatalytic transformations. The library of NCS available is extended by two novel NCSs from Argemone mexicana (AmNCS1, AmNCS2) and one new NCS from Corydalis saxicola (CsNCS); furthermore, it is shown that the NCS from Papaver bracteatum (PbNCS) is a highly productive catalyst leading to the isoquinoline product with up to >99% e.e. Under certain conditions lyophilized whole Escherichia coli cells containing the various overexpressed NCS turned out to be suitable catalysts. The reaction using dopamine as substrate bears several challenges such as the spontaneous non‐stereoselective background reaction and side reactions. The PbNCS enzyme is successfully immobilized on various carriers whereby EziG3 proved to be the best suited for biotransformations. Dopamine showed limited stability in solution resulting in the coating of the catalyst over time, which could be solved by the addition of ascorbic acid (e.g., 1 mg ml −1 ) as antioxidant.