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Glycerate-oxidizing activity of glycolate oxidase from leaves of Spinacia oleracea.

Authors
  • Huang, Jiu-Jiu
  • Wang, Wei-Jun
  • Ye, Jin-Quan
  • Peng, Xin-Xiang
Type
Published Article
Journal
Zhi wu sheng li yu fen zi sheng wu xue xue bao = Journal of plant physiology and molecular biology
Publication Date
Apr 01, 2006
Volume
32
Issue
2
Pages
183–188
Identifiers
PMID: 16622317
Source
Medline
License
Unknown

Abstract

Glycolate oxidase (GO) was purified to homogeneity from leaves of spinach (Spinacia oleracea). Through detecting the consumption of oxygen and the formation of hydrogen peroxide in the assay solution, it was found that GO could also oxidize glycerate, another metabolite in the photorespiratory pathway, and use FMN and FAD, but not riboflavin and lumiflavin, as its cofactors. The optimum reaction pH, Km for glycerate, k(cat) and activation energy of this oxidizing reaction were determined to be 8.0, 7.14 mmol/L, 1.04 s(-1) and 17.29 kJ/mol, respectively. Oxalate and pyruvate at 5.0 mmol/L could inhibit the glycerate-oxidizing activity by 34% and 26%, and oxalate acted as a competitive inhibitor of the glycerate oxidation reaction with a K(i) of 0.75 mmol/L. By the competition plotting with mixed-substrates, it was indicated that glycolate-oxidizing activity and glycerate-oxidizing activity of GO shared the same active site.

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