Ascorbate oxidase II. Sedimentation velocity studies comparing the native, reduced, inactivated and apo-enzyme

Clark, Eloise E.; Poillon, William N.; Dawson, Charles R.

doi:10.1016/s0926-6593(66)80146-7

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Therefore, the molecular weight (68,000) of ascorbate oxidase measured by this technique is not subject to this uncertainty. We believe that the subunit of molecular weight 65,000 first observed in systems at pH 11 (Clark et al, 1966) is the same species that we have observed in both sodium dodecyl sulfate and GuCl treated ascorbate oxidase. Neglecting the 58,000 value obtained in GuCl (for reasons indicated above), the data of Table III indicate a molecular weight of about 65,000 for this subunit.…”

Section: Discussionsupporting

confidence: 79%

“…The native enzyme has no detectable sulfhydryl groups, but on treatment with a suitable denaturant 10 sulfhydryl groups and four disulfide bonds are exposed (Stark and Dawson, 1962). When titrated to pFI 11, ultracentrifuge experiments indicate a decrease in molecular weight to about half that of the native enzyme (Clark et al, 1966), suggesting that ascorbate oxidase possesses a quaternary structure.…”

mentioning

confidence: 99%

“…" Taken fromClark et al (1966).6 Taken fromLee and Dawson (1973a).6 Taken from Wilson(1966).d dodecyl sulfate.…”

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confidence: 99%

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Quaternary structure of ascorbate oxidase

Strothkamp¹,

Dawson²

1974

Biochemistry

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When exposed to either sodium dodecyl sulfate or guanidinium chloride, ascorbate oxidase (molecular weight 140,000, 8-10 copper atoms) dissociates into two copper-free subunits, each of about half the molecular weight of the native enzyme. Removal of the denaturant results in aggregation of the subunits and it has not been found possible to restore the copper and activity. All evidence indicates that the two subunits of molecular weight 65,000, comprising the native enzyme, are identical. Treatment of the native enzyme with sodium dodecyl sulfate and either 2-mercaptoethanol or 2mercaptoethylamine results in two new bands on sodium dodecyl sulfate electrophoresis. The components corresponding to these bands have molecular weights of 38,000 (A chain) and 28,000 (B chain). The same two components are obtained when disulfides of the native enzyme are cleaved with cyanide.

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Section: Discussionsupporting

confidence: 79%

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confidence: 99%

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Quaternary structure of ascorbate oxidase

Strothkamp¹,

Dawson²

1974

Biochemistry

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“…This enzyme is now known as ascorbate oxidase (EC 1.10.3.3) and has been isolated from numerous sources particularly in higher plants. The enzyme is a blue cuproprotein [55] having a molecular weight of 1.4 x 10 9 [56]. The enzyme is a blue cuproprotein [55] having a molecular weight of 1.4 x 10 9 [56].…”

Section: Biochemical Oxidation Of Ascorbic Acidmentioning

confidence: 99%