Details

Autor(en) / Beteiligte

• Yano, Takahiro
• Li, Lin-Sheng
• Weinstein, Edward
• Teh, Jiah-Shin
• Rubin, Harvey

Titel

Steady-state Kinetics and Inhibitory Action of Antitubercular Phenothiazines on Mycobacterium tuberculosis Type-II NADH-Menaquinone Oxidoreductase (NDH-2)

Ist Teil von

• The Journal of biological chemistry, 2006-04, Vol.281 (17), p.11456-11463

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• Type-II NADH-menaquinone oxidoreductase (NDH-2) is an essential respiratory enzyme of the pathogenic bacterium Mycobacterium tuberculosis (Mtb) that plays a pivotal role in its growth. In the present study, we expressed and purified highly active Mtb NDH-2 using a Mycobacterium smegmatis expression system, and the steady-state kinetics and inhibitory actions of phenothiazines were characterized. Purified NDH-2 contains a non-covalently bound flavin adenine dinucleotide cofactor and oxidizes NADH with quinones but does not react with either NADPH or oxygen. Ubiquinone-2 (Q2) and decylubiquinone showed high electron-accepting activity, and the steady-state kinetics and the NADH-Q2 oxidoreductase reaction were found to operate by a ping-pong reaction mechanism. Phenothiazine analogues, trifluoperazine, Compound 1, and Compound 2 inhibit the NADH-Q2 reductase activity with IC50 = 12, 11, and 13 μm, respectively. Trifluoperazine inhibition is non-competitive for NADH, whereas the inhibition kinetics is found to be uncompetitive in terms of Q2.