Simultaneous Spectrophotometric Determination of Iron(II) and Total Iron with 1,10-Phenanthroline

Harvey, Aubrey E.; Smart, Johnson; Amis, E.S.

doi:10.1021/ac60097a009

Cited by 398 publications

(184 citation statements)

References 11 publications

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“…6C (19 p.g of protein) was inactivated as described above with the concentration of formate indicated. After 2 min, the 50-pul preincubation mixture was added to 1 ml of assay mixture to determine the extent of inactivation.…”

Section: Methodsmentioning

confidence: 99%

Formate dehydrogenase from the methane oxidizer Methylosinus trichosporium OB3b

1990

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Formate dehydrogenase (NAD+ depet) was isolated from the obligate methanotroph Methylosinus trichosporium OB3b. When the enzyme was isobted anaerobically, two forms of the enzyme were seen on native polyacrylamide gels, DE-52 celluloe and Sephacryl S-300 colns; they were approximately 315,000 and 155,000 daltons. The enzyme showed two subunits on sodium dodecyl sulfate-polyacrylamide gels. The Mr of the a-subunit was 53,800 ± 2,800, and that of the a-subunit was 102,600 ± 3,900. The enzyme (Mr 315,000) was composed of these subunits in an apparent a2j2 arrangemnt. Nonheme iron was present at a concentration ranging from 11 to 18 g-atoms per mol of enzyme (Mr 315,000). Among the large number of microorganisms that have formate dehydrogenase, the NAD-linked enzyme (EC 1.2.1.2) has been isolated from both facultative methylotrophic bacteria (3, 13) and several yeast species (20; also reference 4 and references therein). There is a great deal of heterogeneity in the structure and composition of bacterial formate dehydrogenases. They range from molecules with two identical subunits and no prosthetic group, found in facultative methylotrophic strains of Moraxella (30) In methylotrophs, formate dehydrogenase is a critical component involved in the oxidative metabolism of methane and methanol. The NADH generated by this enzyme is, in some cases, believed to be the cell's only source of reductant (2). In Methylosinus trichosporium, NAD-linked formate dehydrogenase functions as an in vitro electron donor to methane monooxygenase (32) and indirectly to nitrogenase via a ferredoxin-NAD+ reductase and ferredoxin (9,10) (Fig. 1). Although formate dehydrogenase plays an important role in the metabolism of nonfacultative methylotrophs (and obligate methanotrophs), this enzyme has not yet been isolated from either of these groups of bacteria. In this study we purified the formate dehydrogenase from the obligate methanotroph M. trichosporium and report on its structural and regulatory characteristics. * Corresponding author. MATERIALS AND METHODSGrowth conditions. M. trichosporium OB3b cells used for formate dehydrogenase preparations were batch cultured in 9-liter carboys on nitrate-containing medium (11) as described previously (10). In these cultures, the air-methane mixture (5:1) was dispersed by passing it through stone diffusers and stirring the culture slowly with a magnetic bar. Our cultures did not attain a high density (80 to 120 Klett units, no. 66 filter) in these batch cultures and were harvested by centrifugation after 6 days of growth. After harvesting, the cells were immediately frozen (unwashed)

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Section: Methodsmentioning

confidence: 99%

Formate dehydrogenase from the methane oxidizer Methylosinus trichosporium OB3b

1990

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“…Fe 2+ con cen tra tion in wa ter sam ples was de ter mined in a Thermo Sci en tific spectrophotometer af ter re ac tion with phenanthroline (Harvey et al, 1955).…”

Section: Chemical Determinationsmentioning

confidence: 99%

Geomicrobiology of Acid Mine Drainage in the weathering zone of pyrite-bearing schists in the Rudawy Janowickie Mountains (Poland)

Borkowski

Parafiniuk

Wolicka

et al. 2013

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We re port geomicrobiological anal y sis of acid wa ter res er voirs and Acid Mine Drain age (AMD) de vel oped in the weath er ing zone of py rite-bear ing schists near the closed-down py rite mine in Wieoeciszowice (southwest ern Po land). The anal y sis focused on two res er voirs char ac ter ized by dif fer ent phys i cal and chem i cal prop er ties (pH, re dox po ten tial, con tent of sulphates and heavy met als), em pha siz ing geomicrobiological re la tion ships tak ing place in this AMD set ting and de scrib ing the mi cro bi o log i cal pro cesses that sig nif i cantly in flu ence biogeochemical cy cles of sul phur and iron in the wa ter res er voirs ana lysed. The res er voir wa ter also har bours nu mer ous large, or ga nized mi cro bial struc tures in the form of stream ers, studied in de tail here us ing op ti cal and elec tron mi cros copy and by mi cro bi o log i cal cul ti va tion and mo lec u lar meth ods. The Wieoeciszowice mine slime stream ers are char ac ter ized by the co-oc cur rence of typ i cal chemolithoautotrophic mi cro or ganisms ox i diz ing sul phur and iron to gether with sul phate-re duc ing bac te ria. These struc tures prob a bly de pend on the oc currence of iron(II) in the sur round ing en vi ron ment.

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“…The following components react with Fe(II): 2,2′-bipirydyl forming a red complex with the maximum absorption at 520 nm (Whitehead and Malik 1975) and 1,10-phenanthroline, also forming a red complex with the maximum absorption of approx. 510 nm (Harvey et al 1955;Lozano-Camargo et al 2007). In turn, thiocyanate ions and Fe(III) form a red complex with the maximum absorption at 475-485 nm (Tarafder and Thakur 2005), while 1,10-phenanthroline forms a yellow complex with the maximum absorption of 396 nm (Harvey et al 1955).…”

Section: Introductionmentioning

confidence: 99%

“…510 nm (Harvey et al 1955;Lozano-Camargo et al 2007). In turn, thiocyanate ions and Fe(III) form a red complex with the maximum absorption at 475-485 nm (Tarafder and Thakur 2005), while 1,10-phenanthroline forms a yellow complex with the maximum absorption of 396 nm (Harvey et al 1955).…”

Section: Introductionmentioning

confidence: 99%

“…For instance, the method based on iron reaction with 1,10-phenanthroline has been used in selective determinations of Fe(II) and Fe(III) contents. The above method uses both the fact of forming multi-coloured complexes determined sequentially at different wavelengths: 396 and 512 nm for Fe(III) and Fe(II), respectively (Harvey et al 1955), and sequential determinations of Fe(II) and total iron following the reduction of Fe(III) to Fe(II) (Feres and Reis 2005;Galhardo and Masini 2001). 1,10-Phenanthroline has also been used in sequential determination of iron forms in direct colorimetric determinations combined with colorimetric titration (Kochana and Parczewski 1997).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Determination of Iron Species in Samples of Iron-Fortified Food

et al. 2014

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The paper presents the determination of iron forms in food products. The procedure of sample extraction was developed and optimized, preserving the content of particular forms of iron. The colorimetric method using 2,2′-bipirydyl (measurements at 520 nm) was applied in Fe(II) determinations, while in Fe(III) determinations, the colorimetric method with potassium thiocyanate (measurements at 470 nm) was applied. The total content of iron was determined by the technique of atomic absorption spectrometry, which allowed for the determination of iron content in organic and inorganic complex compounds. Detection limits of 1 mg kg −1 were obtained for all determined iron forms, with the precision ranging between 0.7 % and 1.5 % for 10 mg kg −1 concentration. The optimized analytical procedure was applied in the determinations of iron forms in iron-fortified food products.

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Simultaneous Spectrophotometric Determination of Iron(II) and Total Iron with 1,10-Phenanthroline

Cited by 398 publications

References 11 publications

Formate dehydrogenase from the methane oxidizer Methylosinus trichosporium OB3b

Formate dehydrogenase from the methane oxidizer Methylosinus trichosporium OB3b

Geomicrobiology of Acid Mine Drainage in the weathering zone of pyrite-bearing schists in the Rudawy Janowickie Mountains (Poland)

Determination of Iron Species in Samples of Iron-Fortified Food

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