Manganese-catalyzed Oxidations of 2,3-Diketogulonate<sup>*</sup>

Homann, Peter H.

doi:10.1021/bi00885a031

Cited by 15 publications

(6 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although Homann has stated that "the Mn3+ pyrophosphate complex itself is virtually ineffective as initiator of an autoxidation of DKGA" [12], we have found that a rapid oxygen uptake follows the addition of manganipyrophosphate to solutions of DKGA. Initial rates of oxygen consumption, as well as total oxygen consumed, are proportional to the amount of Mn3+ added.…”

Section: Dark Oxidation Of Dkga By Mn3+contrasting

confidence: 61%

Kinetics of Chloroplast‐mediated Photoxidation of Diketogulonate*

Habermann

Handel

McKELLAR

1968

Photochem & Photobiology

View full text Add to dashboard Cite

Illuminated chloroplasts can mediate a photoxidation of diketogulonic acid (DKGA) with rates of oxygen uptake equivalent to rates of Hill reactions with ferricyanide or quinone. The photoxidation of DKGA is sensitive to dichlorophenyl dimethylurea (DCMU) and exhibits the drop in quantum yield at long wavelengths characteristic of photosystem 11. Still, the reaction is only partially inactivated by heating chloroplasts at 50" for 10 min (which destroys oxygen evolution). The photoxidation is inhibited by copper and detergents; and is stimulated by added flavin (or methyl viologen) and manganous ions.A model system containing Mn3+ (as manganipyrophosphate) and DKGA, mimics the chloroplast system. Pre-illuminated chloroplast suspensions can be substituted for Mn3+ in the model dark reaction.I t seems that a light-dependent oxidation of MnZ+ to Mn3+ by photosystem I1 is the essential contribution of the chloroplasts. Electrons from Mn2+ move through the electron transport system to femcyanide or to photosystem I where, via flavin (or methyl viologen), oxygen is reduced to H,O,.

show abstract

Section: Dark Oxidation Of Dkga By Mn3+contrasting

confidence: 61%

Kinetics of Chloroplast‐mediated Photoxidation of Diketogulonate*

Habermann

Handel

McKELLAR

1968

Photochem & Photobiology

View full text Add to dashboard Cite

show abstract

“…In vitro studies (5, 20-22) have shown that the E. coli apoMnSOD can bind either Mn(II) or Fe(II), but that only the former imparts catalytic activity. Moreover, O2oxidizes Mn(II) to Mn(III) (2,12,15,16,29) but reduces Fe(III) to Fe(II) whether that iron is in cytochrome c (3), hemoglobin (27), or the EDTA complex (13). In accord with the proposal we will develop below, it has been shown that in Staphylococcus aureus manganese becomes oxidized to Mn(III) in aerobic cells and reduced to Mn(II) in anaerobic cells (7a).…”

Section: Discussionmentioning

confidence: 99%

Induction of superoxide dismutases in Escherichia coli B by metal chelators

Pugh¹,

Fridovich²

1985

J Bacteriol

View full text Add to dashboard Cite

The effects of metal salts, chelating agents, and paraquat on the superoxide dismutases (SODs) ofEscherichia coli B were explored. Mn(II) increased manganese-containing SOD (MnSOD), whereas Fe(II) increased iron-containing SOD (FeSOD). Chelating agents induced MnSOD but decreased FeSOD and markedly increased the degree of induction seen with Mn(H). Paraquat also exerted a synergistic effect with Mn(II). High levels of MnSOD were achieved in the combined presence of Mn(II), chelating agent, and paraquat. All of these effects were dependent on the presence of oxygen. MnSOD, not ordinarily present in anaerobicaly grown E. coli cells, was present when the cells were grown anaerobically in the presence of chelating agents. These results are accommodated by a scheme which incorporates autogenous repression by the apoSODs and competition between Fe(H) and Mn(ll) for the metal-binding sites of the apoSODs. It is further supposed that oxygenation and intracellular O2 production favor MnSOD production because O2 oxidizes Mn(H) to Mn(III), which competes favorably with Fe(H) for the apoSODs. Escherichia coli produces two distinct homodimeric SODs. One of these contains iron (FeSOD) (25, 25a, 30), and the other contains manganese (MnSOD) (14, 26). When grown anaerobically, E. coli cells contain only FeSOD, but when grown aerobically they contain FeSOD, MnSOD, and a hybrid of these (HySOD) (9). Redox-active compounds,

show abstract

“…The procedure described herein is based on a specific requirement for Mn(II) in the photo-oxidation of DGA, as first noted by Habermann, Gaffron, and Homann (10-12). Oxidation of DGA has also been observed in several nonphotochemical reactions, with the presence of Mn(II) ions being a specific requirement (13). One of these reactions involved the presence of the enzyme horseradish peroxidase (HRP), H202 being one of the oxidation products.…”

mentioning

confidence: 99%

“…In view of the existence of well-characterized fluorometric methods for determination of H202 (5,14), it appeared possible to couple the fluorometric H202 assay to the Mn(II)-catalyzed oxidation of DGA. Moreover, the use of HRP in the H202 assay suggested that HRP could serve a "double purpose" in this system, since HRP is also required in the "dark" oxidation of DGA (13). A particularly attractive feature of this reaction system was its great selectivity for Mn(II) (13), enabling its determination in the presence of other metal ions that interfere in chemiluminescence methods; moreover, no prior conversion of Mn(II) to other species (e.g., Mn04~) was required.…”

mentioning

confidence: 99%

“…Moreover, the use of HRP in the H202 assay suggested that HRP could serve a "double purpose" in this system, since HRP is also required in the "dark" oxidation of DGA (13). A particularly attractive feature of this reaction system was its great selectivity for Mn(II) (13), enabling its determination in the presence of other metal ions that interfere in chemiluminescence methods; moreover, no prior conversion of Mn(II) to other species (e.g., Mn04~) was required. This paper describes use of the HRP/DGA reaction system for fluorometric Mn(II) determinations.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Fluorometric determination of manganese(II) via catalyzed enzymic oxidation of 2,3-diketogulonate

Biddle¹,

Wehry²

1978

Anal. Chem.

View full text Add to dashboard Cite

of 488.1 nm and 514.5 nm are available. Moreover, as the existences of small amounts of foreign metals might cause large errors, a complete separation will become an important requirement.The laser-induced photoacoustic absorption method is applicable to a wide range of liquid samples and application of lasers operating in the UV, visible, and IR is recommended.Further development in surface pre-treatment of piezoelectric ceramic is needed in order to measure materials in concentrated acidic and basic media. Then, ultra trace determinations of various kinds of metals beside cadmium and organic compounds would become possible utilizing the laser-induced photoacoustic absorption method. ACKNOWLEDGMENTWe are greatly indebted to S. Toda and Y. Dokiya of the Faculty of Agriculture, The University of Tokyo, for providing heavy metal-tolerant fungus as samples, and are also grateful to M. Suzuki for her help in atomic absorption measurements. LITERATURE CITEDA fluorometric technique for the determination of Mn(I1) is reported. The specific requirement for Mn(I1) in the peroxidase-catalyzed Oxidation of 2,3-diketogulonate is utilized to produce H,Oz, and the signal observed in the concurrent fluorometric Hz02 "fixed time" assay procedure is related to the Mn( 11) concentration using a modified standard addition method. The utility of this procedure is demonstrated at pH 8.0 and 25 O C in a synthetic seawater matrix wherein the detection limit Is 8 pM Mn( 11); accurate determinations can be performed up to ca. 50 pM Mn(11). Analysis time is less than 30 min.

show abstract

Manganese-catalyzed Oxidations of 2,3-Diketogulonate^*

Cited by 15 publications

References 28 publications

Kinetics of Chloroplast‐mediated Photoxidation of Diketogulonate*

Kinetics of Chloroplast‐mediated Photoxidation of Diketogulonate*

Induction of superoxide dismutases in Escherichia coli B by metal chelators

Fluorometric determination of manganese(II) via catalyzed enzymic oxidation of 2,3-diketogulonate

Contact Info

Product

Resources

About

Manganese-catalyzed Oxidations of 2,3-Diketogulonate*

Cited by 15 publications

References 28 publications

Kinetics of Chloroplast‐mediated Photoxidation of Diketogulonate*

Kinetics of Chloroplast‐mediated Photoxidation of Diketogulonate*

Induction of superoxide dismutases in Escherichia coli B by metal chelators

Fluorometric determination of manganese(II) via catalyzed enzymic oxidation of 2,3-diketogulonate

Contact Info

Product

Resources

About

Manganese-catalyzed Oxidations of 2,3-Diketogulonate^*