Synthesis and Biochemical Evaluation of Nicotinamide Derivatives as NADH Analogue Coenzymes in Ene Reductase

Abstract

Nicotinamide and pyridine‐containing conjugates have attracted a lot of attention in research as they have found use in a wide range of applications including as redox flow batteries and calcium channel blockers, in biocatalysis, and in metabolism. The interesting redox character of the compounds’ pyridine/dihydropyridine system allows them to possess very similar characteristics to the natural chiral redox agents NAD+/NADH, even mimicking their functions. There has been considerable interest in designing and synthesizing NAD+/NADH mimetics with similar redox properties. In this research, three nicotinamide conjugates were designed, synthesized, and characterized. Molecular structures obtained through X‐ray crystallography were obtained for two of the conjugates, thereby providing more detail on the bonding and structure of the compounds. The compounds were then further evaluated for biochemical properties, and it was found that one of the conjugates possessed similar functions and characteristics to the natural NADH. This compound was evaluated in the active enzyme, enoate reductase; like NADH, it was shown to help reduce the C=C double bond of three substrates and even outperformed the natural coenzyme. Kinetic data are reported.

Transfer hydrogenations catalyzed by streptavidin-hosted secondary amine organocatalysts

“…6,7 In an alternative and potentially simpler approach, small organic molecules can be used as hydride donors, 8,9 such as the Hantzsch ester, 10 dihydro-benzylnicotinamide (BNAH) and their derivatives. 11,12 Nevertheless, there are only a handful of proteinbased catalysts reported to use simple hydride donors for reactions, including ene-reductases (ERs), 6,13 salicylate (SalH), para-hydroxybenzoate (PHBH) and hydroxybenzoate (3HB6H) hydroxylases, 14 cytochrome P450, 15 2-hydroxybiphenyl 3-monooxygenase (HbpA), 16 Old Yellow Enzyme (TsOYE), 17 and glucose dehydrogenases (GDH). 18 Here, we aim to expand this collection by proving the concept that organocatalytic artificial enzymes can catalyze transfer hydrogenation using BNAH as a hydride source.…”

Asymmetric Reduction of (R)‐Carvone through a Thermostable and Organic‐Solvent‐Tolerant Ene‐Reductase

“…This calculation procedure was used for all subsequent activity data. The kinetic data fit to a clear kinetic profile according to the Michaelis–Menten model as is typical for ERs . A number of potential substrates was screened and compared with the standard (Table , Figure S3).…”

Applying Non-canonical Redox Cofactors in Fermentation Processes

“…When performing in vitro biocatalytic processes, several factors such as cost, solubility, instability, or restricted activity of cofactors may impede further development of enzymes ( Paul et al., 2014 ; Paul and Hollmann, 2016 ; Guarneri et al., 2019 ). Shorter versions of NADH, varying substituents on the dihydropyridine ring and nitrogen ( Figure 2 A), were synthesized and used as cofactor biomimetics with oxidoreductase enzymes to catalyze the reduction of carbon-carbon double bonds ( Paul et al., 2013 ; Löw et al., 2016 ; Knaus et al., 2016 ; Falcone et al., 2019 ), the hydroxylation of benzoates ( Ryan et al., 2008 ; Guarneri et al., 2020 ), or the oxidation of glucose ( Nowak et al., 2017 ; Huang et al., 2019 ). These nicotinamide cofactor biomimetics allow for an orthogonal system when using enzymes as cell-free extracts for the reduction of carbon-carbon double bonds: activity by other oxidoreductases such as alcohol dehydrogenases was excluded, as these enzymes do not function with those truncated cofactors ( Josa-Culleré et al., 2019 ; Paul et al., 2013 ).…”