Sulfhydryl groups, disulfide bridges and the state of copper in three blue oxidases

Briving, Carin; Deinum, J.

doi:10.1016/0014-5793(75)80851-9

Cited by 20 publications

(7 citation statements)

References 19 publications

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“…24 The data for the copper thiaether complexes show that, despite an enormous range of geometric constraints about the copper center (trigonal, square planar, square pyrimadal, C2v, pseudooctahedral, flattened tetrahedral), changes in the number of sulfur donors present from one to six, and variations in the number and types of nonsulfur donor groups, the frequency of the copper-thiaether sulfur stretching vibration varies only between 247 and 282 cm-1. The copper ion lies well above the plane of the four sulfur atoms in the [12]aneS4, [13]aneS4, and presumably [12]aneSg complexes25 compared to its in-plane position in the [14]aneS4 complex26 and, presumably, the larger macrocycles. The (Et)2TTU complex is nonmacrocyclic and the sulfur donors are arranged in a very flat tetrahedral (¿>24) geometry.…”

Section: Resultsmentioning

confidence: 97%

Resonance Raman spectra of copper-sulfur complexes and the blue copper protein question

Ferris¹,

Woodruff²,

Rorabacher³

et al. 1978

J. Am. Chem. Soc.

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Section: Resultsmentioning

confidence: 97%

Resonance Raman spectra of copper-sulfur complexes and the blue copper protein question

Ferris¹,

Woodruff²,

Rorabacher³

et al. 1978

J. Am. Chem. Soc.

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“…Especially for half-cystine we detected 12.3 compared to 17.8 residues, whereas almost no difference exists for methionine. So far we have not Taken from Stark and Dawson [39] analysed for the content of accessible compared to inaccessible sulfhydryl groups, as was done earlier by Stark and Dawson [39] or Briving and Deinum [41] for tree and fungal laccase. In the case of ascorbate oxidase from yellow squash 10-12 cysteine residues plus 6 -8 half-cystine residues have been analysed with no -SH group accessible to mercurials [39].…”

Section: Amino Acid Cornpositonmentioning

confidence: 99%

“…In the case of ascorbate oxidase from yellow squash 10-12 cysteine residues plus 6 -8 half-cystine residues have been analysed with no -SH group accessible to mercurials [39]. For tree and fungal laccase 5 -7 half-cystine residues including 1 accessible -SH group have been found [41]. Our value obtained for half-cystine (12, Table 2) represents about twice the amount of half-cystine determined for the laccases by Briving and Deinum…”

Section: Amino Acid Cornpositonmentioning

confidence: 99%

Ascorbate Oxidase from Cucurbita pepo medullosa

Marchesini¹,

Kroneck²

1979

European Journal of Biochemistry

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1. Ascorbate oxidase has been isolated from the green squash Cucurbitapepo medullosa by a new purification method. Furthermore a low-molecular-weight copper protein containing one type-1 copper/20 000 M, could be separated during the purification of the oxidase. The six-step procedure developed improved the yield of ascorbate oxidase by a factor of 2.5. The method is well reproducible and a constant value of 8 Cu (7.95 f 0.11140000 MI) has been established. By ultracentrifugal and electrophoretic criteria the enzyme preparations have been found to be homogeneous. They exhibited a specific activity of 3930 2. The pure enzyme is characterized by the following optical purity indices: A2so/Ablo = 25 +_ 0.5, A330/A610 = 0.65 & 0.05 and A6I0/A500 = 7.0 & 0.25. The molar absorption coefficient of the characteristic absorption maximum at 610 nm (oxidized minus reduced) amounts to 9700 M-' em-'.3. Computer simulations of the electron paramagnetic resonance (EPR) spectra of the oxidized enzyme reveal the following parameters: for the type-1 (blue) copper gz = 2.227, g , = 2.058, g, = 2.036; A , = 5.0 mT, A , = A , = 0.5 mT, for the type-2 (non-blue) copper gli = 2.242, g l = 2.053; All = 19.0 mT, A1 = 0.5 mT. Out of the eight copper atoms present in the oxidase four are detectable by EPR. Of these, three belong to the type-1 class, and one to the type-2 class, as demonstrated by computer simulations of the EPR spectra.4. To achieve full reduction of the enzyme, as measured by bleaching of the blue chromophore, four equivalents of L-ascorbate or reductate must be added in the absence of molecular oxygen. Upon reduction of the enzyme the fluorescence at 330 nm (%ax = 295 nm) is enhanced by a factor of 1.5 to 1.75. The reduced enzyme is readily reoxidized by dioxygen, ferricyanide or hydrogen peroxide. It binds two molecules of hydrogen peroxide in the oxidized state (l/type-3 Cu pair), which can be monitored by a characteristic increase of the absorbance around 310 nm ( A s = 1000 f 50 M-'

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“…The amino acid analysis revealed a comparatively high amount of cysteic acid corresponding to 11 and 18 mol of half-cystine residues for laccases I1 and 111 respectively. No free sulfhydryl groups could be detected upon reaction with -SH reagents [5,5'-dithio-bis(2nitrobenzoic acid and chloromercuribenzoic acid] in contrast to one sulfhydryl group in each, laccases A and B, of Trametes versicolor [31]. Thus the cysteic acid should have originated from cystine residues.…”

Section: Amino Acid Compositionmentioning

confidence: 98%

The Phenoloxidases of the Ascomycete Podospora anserina. Structural Differences between Laccases of High and Low Molecular Weight

1978

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In order to investigate the extent of the relationship between the three copper-containing glycoproteins, laccases I, I1 and I11 ( M I 70000,80000 and 390000 respectively) of Podospora anserina, the following experiments were carried out on laccases I1 and 111: (a) determination of amino acid composition ; (b) determination of N-terminal and C-terminal amino acid ; (c) determination of sugar composition; (d) dissociation studies on native and denatured laccases and also after removal of copper from the enzymes; (e) digestion of the carbohydrate moieties with the aid of glycosylhydrolases.A comparison between the results of these experiments and data previously obtained with laccase I allows the following conclusions to be drawn.

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Sulfhydryl groups, disulfide bridges and the state of copper in three blue oxidases

Cited by 20 publications

References 19 publications

Resonance Raman spectra of copper-sulfur complexes and the blue copper protein question

Resonance Raman spectra of copper-sulfur complexes and the blue copper protein question

Ascorbate Oxidase from Cucurbita pepo medullosa

The Phenoloxidases of the Ascomycete Podospora anserina. Structural Differences between Laccases of High and Low Molecular Weight

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