• Archives of Pharmacal Research
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• v.20 no.6
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• pp.590-596
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• 1997

The NADH reductase component of the steroid 9.alpha.-hydroxylase from Mycobacterium fortuitum was purified to homogeneity. Recovery of the enzyme from the 50-60% ammonium sulfate saturated fraction was 49%, with a purification factor of 100-fold. The NADH reductase has a relative molecular of 60 KDa as determined by SDS-PAGE. The absorption maxima at 410 and 450 nm indicate the presence of iron-sulfur group and flavin. These prosthetic groups seemed to function as redox groups that transfer electrons from NADH to the following protein. The $K_M$ value for NADH as substrate was $68{\mu}M$. The $NH_2$-terminal amino acid sequence of the reductase was determined as Met-Asp-Ala-Ile-Thr-Asn-Val-Pro-Leu-Pro-Ala-Asn-Glu-Pro-Val-His-Asp-Tyr-Ala-Thr. This sequence does not show a homology with the $NH_2$ -terminal sequences reported for the reductase component of other monooxygenases, suggesting that the NADH reductase component of the steroid 9.alpha.-hydroxylase system is novel.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.707-714
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• 2023

Plant-derived insecticide-neonicotinoid insecticides (NIs) played a crucial role in the development of agriculture and food industry in recent years. Nevertheless, synthesis of these nitrogen-containing heterocyclic compounds with an effective and greener routing remains challenging especially to the notion raise of "green chemistry" and "atom economy". While bio-catalyzed methods mediated by nicotinate dehydrogenase (NDHase) then provide an alternative. The current review mainly focuses on the introduction of sources, components, structure, catalytic mechanism and applications of NDHase. Specifically, NDHase is known as nicotinic acid hydroxylase and the sources principally derived from phylum Proteobacteria. In addition, NDHase requires the participation of the electron respiratory chain system on the cell membrane. And the most important components of the electron respiratory chain are hydrogen carrier, which is mainly composed of iron-sulfur proteins (Fe-S), flavin dehydrogenase (FAD), molybdenum binding protein and cytochromes. Heterologous expression studies were hampered by the plasmid and host with high efficiency and currently only Pseudomonas entomophila L48 as well as Comamonas testosterone was successfully utilized for the expression of NDHase. Furthermore, it is speculated that the conjugate and inductive effects of the substituent group at position 3 of the substrate pyridine ring exerts a critical role in the hydroxylation reactions at position 6 concerning about the substrate molecular recognition mechanism. Finally, applications of NDHase are addressed in terms of pesticide industry and wastewater treatment. On conclusion, this critical review would not only deepen our understanding of the theory about NDHase, but also provides the guideline for future investigation of NDHase.