49 by: Caitlin Brown

Student – Caitlin Brown

Enzyme: Nicotinate Dehydrogenase

EC number: 1.17.1.5

Nicotinate dehydrogenase is found in Bacteria, Archaea, Eukaryota. For this project I will be focusing on its role in the bacteria Pseudomonas fluorescens. Nicotinate dehydrogenase is found in the cell membrane of Pseudomonas fluorescens.

The enzyme catalyzes the hydroxylation of Nicotinate to 6-hydroxynicotinate in the presence of H₂O and NADP⁺, CuCl₂ completely inhibits the enzyme after 10 minutes in concentrations of 1mM at 35°C. Other inhibitors include 2,2′-dipyridyl, Acriflavin, AgNO₃, HgCl₂, KCN, N-ethylmalemide, NaN₃, p-chloromercuribenzoate, phenylhydrazine.

The hydroxylation mechanism by nicotinate dehydrogenase needs further study, but some research suggests a 2Fe-2S protein center and a flavin and molybdenum binding site. Due to the presence of the molybdenum binding site, the enzyme can split H₂O creating an alcohol group that may nucleophilically attack nitrogen containing cyclic structures.

References

1. Wagener, N., Pierik, A.J., Hille, R., Dobbek, H. (2009, June 30). Crystal Structure of Nicotinate Dehydrogenase. RCSB Protein Data Bank. https://www.rcsb.org/structure/3HRD
2. Leibniz Institute. (2023, January). Information on EC 1.17.1.5 – nicotinate dehydrogenase. BRENDA. https://www.brenda-enzymes.org/enzyme.php?ecno=1.17.1.5#CAS%20REGISTRY%20NUMBER
3. Leibniz Institute. (2023, January). Literature summary for 1.17.1.5 extracted from “Purification and characterization of nicotinic acid dehydrogenase from Pseudomonas fluorescens TN5 (1994), J. Ferment. Bioeng., 78, 19-26″. BRENDA https://www.brenda-enzymes.org/literature.php?e=1.17.1.5&r=644529
4. Chen, Z., Xu, X., Ju, X., Yan, L., Li, L., & Yang, L. (2023). Sources, Components, Structure, Catalytic Mechanism and Applications: a Critical Review on Nicotinate Dehydrogenase. J Microbiol Biotechnol. 33(6),707-714. doi: 10.4014/jmb.2302.02011. https://pmc.ncbi.nlm.nih.gov/articles/PMC10331938/#sec9