FEBS Letters | |
Kinetic and spectral properties of pea cytosolic ascorbate peroxidase | |
Dunford, H.Brian1  Zilinskas, Barbara A.2  Marquez, Leah A.1  Quitoriano, Mannix2  | |
[1] Department of Chemistry, University of Alberta, Edmonton, Alta., Canada T6G 2G2;Department of Plant Science, Cook College, Rutgers University, New Brunswick, NJ 08903-0231, USA | |
关键词: Compound I; Compound II; Transient state kinetics; Optical spectra; Ascorbate oxidation; pH dependence; Cytochrome c peroxidase; comparison; | |
DOI : 10.1016/0014-5793(96)00562-5 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Sufficient highly purified native pea cytosolic ascorbate peroxidase was obtained to characterize some of its kinetic and spectral properties. Its rate constant for compound I formation from reaction with H2O2 is 4.0 × 107 M−1 s−1, somewhat faster than is typical for peroxidases. Compound I has the typical optical spectrum of an iron(IV)-porphyrin-π-cation radical, despite considerable homology with yeast cytochrome c peroxidase. The rate constant for compound I reduction by ascorbate is extremely fast (8.0 × 107 M−1 s−1 at pH 7.8), again in marked contrast to the behavior of the yeast enzyme. The pH-rate profile for compound I formation indicates a pK a value of 5.0 for a group affecting the active site reaction.
【 授权许可】
Unknown
【 预 览 】
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RO201912020302908ZK.pdf | 395KB | download |