Abstract
Two catechol oxidases have been isolated from sweet potatoes (Ipomoea batatas) and purified to homogeneity. The two isozymes have been characterized by EXAFS, EPR-, UV/Vis-spectroscopy, isoelectric focusing, and MALDI-MS and have been shown to contain a dinuclear copper center. Both are monomers with a molecular mass of 39 kDa and 40 kDa, respectively. Substrate specificity and NH2-terminal sequences have been determined. EXAFS data for the 39 kDa enzyme reveal a coordination number of four for each Cu in the resting form and suggest a Cu(II)-Cu(II) distance of 2.9 A for the native met form and 3.8 A for the oxy form.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Catechol Oxidase / chemistry*
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Catechol Oxidase / isolation & purification
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Catechol Oxidase / metabolism*
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Chromatography, Ion Exchange
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Copper / analysis*
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Electron Probe Microanalysis
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Electron Spin Resonance Spectroscopy
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Electrophoresis, Polyacrylamide Gel
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Molecular Weight
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Peptide Fragments / chemistry
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Plant Roots
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Protein Conformation
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Sequence Alignment
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Solanaceae / enzymology*
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Solanum tuberosum
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Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Spectrophotometry
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Substrate Specificity
Substances
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Peptide Fragments
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Copper
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Catechol Oxidase