Dissertation Redesign for Scholarly Practitioners in Educational Leadership

MacGregor, Cynthia J.; Fellabaum, Jennifer

doi:10.4018/978-1-5225-0445-0.ch005

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…The assay of nitrate reductase was carried out at 70°C using reduced forms of methyl viologen as reductant as described in [17]. Specific activity of nitrate reductase was expressed as μmol NO 2 formed per min per mg of protein.…”

Section: Methodsmentioning

confidence: 99%

Molybdenum‐free nitrate reductases from vanadate‐reducing bacteria

et al. 1998

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Two catalytically distinct molybdenum-free dissimilatory nitrate reductases, a soluble periplasmic and a membranebound one, were isolated from the vanadate-reducing facultatively anaerobic bacterium Pseudomonas isachenkovii and purified to electrophoretic homogeneity. The enzymes did not contain molybdenum, the periplasmic enzyme contained vanadium, whereas the membrane-bound enzyme was vanadium-free. Both nitrate reductases lacked molybdenum cofactor. This fact was proved by reconstitution of the apoprotein of the nitrate reductase of Neurospora crassa nit-1 mutant. This is the first demonstration of molybdenum-free and molybdenum cofactorfree nitrate reductases.z 1998 Federation of European Biochemical Societies.

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Section: Methodsmentioning

confidence: 99%

Molybdenum‐free nitrate reductases from vanadate‐reducing bacteria

et al. 1998

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“…The standard assay of nitrate reductase was carried at 30°C, using reduced Methyl Viologen as the electron donor, by a modification of the method described by MacGregor (1978). After preliminary experiments designed to prolong the linearity of product formation with time, the assay was modified by the inclusion of cyanate (1 mM) (see below).…”

Section: Assay Of Nitrate Reductase Activitymentioning

confidence: 99%

Purification and characterization of the assimilatory nitrate reductase of Azotobacter vinelandii

Gangeswaran

Lowe

Eady

1993

Biochemical Journal

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1. A soluble reduced Methyl Viologen-dependent assimilatory nitrate reductase from Azotobacter vinelandii strain UW136 grown aerobically on nitrate was purified to homogeneity by the criteria of nitrate reductase activity staining, and coincidence of a Coomassie Blue-staining protein band on polyacrylamide gels run under non-denaturing conditions. The specific activity was 3 mumol of NO2- formed/min per mg of protein. 2. Gel filtration on Superose-12 and SDS/PAGE showed that the enzyme had an M(r) of 105,000 and was monomeric. The enzyme contained 1 Mo atom, 4 Fe atoms and 4 acid-labile sulphide atoms per molecule; no evidence for the presence of cytochrome or FAD was found. 3. Mo was present in a molybdenum cofactor, which on extraction was capable of activating apo-(nit-1) nitrate reductase present in crude extracts of nit-1 mutants of Neurospora crassa. 4. As isolated, the enzyme had e.p.r. signals assigned to Mo(V) with g-values g1 = 2.023; g2 = 1.998; g3 = 1.993 and with gav. = 2.004 indicating an unusual environment of Mo in this enzyme. 5. Reduction with S2O4(2-) bleached the e.p.r. signals which, on reoxidation after the addition of NO3(2-) to initiate enzyme turnover, exhibited at short times Mo(V) signals similar to those of dissimilatory nitrate reductases, with g1 = 1.998; g2 = 1.989; g3 = 1.981 and gav. = 1.989. Prolonged incubation subsequently gave a mixture of both e.p.r. species. 6. Neither NADH nor NADPH was effective as an electron donor, but reduced Methyl Viologen (apparent Km 998 microM) and reduced Bromophenol Blue (apparent Km 158 microM) were effective. With these donors the apparent Km values for nitrate were 70 microM and 217 microM respectively.

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