Enzymatic synthesis of high-titer nicotinamide mononucleotide with a new nicotinamide riboside kinase and an efficient ATP regeneration system.
Level 5 - mechanism / opinion, no new human data
In vitro biocatalytic and enzyme characterization study (no human or animal data).
PubMed 38647612 · doi:10.1186/s40643-022-00514-6
What was done
Researchers identified and purified a novel nicotinamide riboside kinase (Klm-NRK) from the yeast Kluyveromyces marxianus to convert chemically synthesized nicotinamide riboside (NR) into nicotinamide mononucleotide (NMN). They characterized the enzyme's specific activity, optimal pH, thermal stability, and kinetic parameters (kcat/KM) toward ATP and NR. They then coupled Klm-NRK with an acetate kinase/acetyl phosphate (AcK/AcP) ATP regeneration system to evaluate complete batch conversion of high-concentration NR (100 g·L⁻¹) into NMN.
What was found
Purified Klm-NRK demonstrated a specific activity of 7.9 U·mg⁻¹ protein, an optimal pH of 7.0 in potassium phosphate buffer, and a half-life of 7.29 hours at 50 °C. The catalytic efficiencies (kcat/KM) were 57.4 s⁻¹·mM⁻¹ for ATP and 84.4 s⁻¹·mM⁻¹ for NR. Coupled with the ATP regeneration system, the reaction achieved complete phosphorylation of 100 g·L⁻¹ NR within 8 hours, yielding an 84.2% molar isolation yield and a space-time yield of 281 g·L⁻¹·day⁻¹.
Why it matters
Industrial production of NMN has been hampered by hazardous chemical phosphorylation methods and low fermentation yields. This biocatalytic route provides a high-titer, high-yield enzymatic process for large-scale NMN synthesis using an enzyme with high catalytic efficiency and stability.
Limits
The study is restricted to laboratory-scale in vitro biocatalysis and does not report performance in pilot or industrial-scale bioreactors. Economic viability, downstream purification costs, enzyme recyclability, and comparative cost-efficiency relative to existing commercial manufacturing methods were not detailed in the abstract.
Cited by
- supports Nicotinamide riboside (NR) is a molecule that lacks a phosphate group compared to NMN and must first be phosphorylated into NMN before being synthesized into NAD.
- supports Nicotinamide mononucleotide (NMN) is harder to synthesize than nicotinamide riboside because it is a larger molecule containing a phosphate group requiring difficult phosphate chemistry.