Kinetic studies of the copper nitrite reductase from Achromobacter cycloclastes and its interaction with a blue copper protein.
Transient state, burst and steady state kinetics of reactions of the blue copper nitrite reductase (NIR) and blue copper protein from Achromobacter cycloclastes are investigated. The two copper-containing species are reacted with each other and where possible with dithionite, ascorbate and nitrite. Both copper proteins are fully reduced by dithionite with both S2O4(2-) and SO2-. species active. NIR is only partially reduced by ascorbate in an unusual biphasic reaction consistent with complete reduction of type-one copper followed by partial reduction of type-two copper. The rate of reduction of the type-one copper is accelerated using phenazine methosulfate as mediator. Nitrite can oxidize dithionite-reduced NIR but cannot reduce oxidized NIR. Rate constants were determined for all observed reactions.
D000421:Alcaligenes / Q000201:enzymology*; D001205:Ascorbic Acid / Q000494:pharmacology; D001426:Bacterial Proteins; D004227:Dithionite / Q000494:pharmacology; D007700:Kinetics; D008667:Metalloproteins / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D009572:Nitrite Reductases / Q000378:metabolism*
D001426:Bacterial Proteins; D008667:Metalloproteins; C017079:mauC protein, Methylobacterium extorquens; D004227:Dithionite; D009247:NADH, NADPH Oxidoreductases; D009572:Nitrite Reductases; C052695:nitrite reductase, copper-containing; D001205:Ascorbic Acid