A Specific Ascorbate Free Radical Reductase Isozyme Participates in the Regeneration of Ascorbate for Scavenging Toxic Oxygen Species in Potato Tuber Mitochondria

Autor:	Giuseppe Borraccino, Silvio Dipierro, S De Leonardis, G. De Lorenzo
Rok vydání:	1995
Předmět:	chemistry.chemical_classification Molecular mass Physiology Effector fungi food and beverages Plant Science Mitochondrion Reductase Biology biology.organism_classification Isozyme Cytosol Enzyme Biochemistry chemistry Genetics Solanaceae Research Article
Zdroj:	Plant Physiology. 109:847-851
ISSN:	1532-2548 0032-0889
DOI:	10.1104/pp.109.3.847
Popis:	Ascorbate free radical (AFR) reductase from isolated potato tuber (Solanum tuberosum L.) mitochondria was studied. The enzyme was purified to homogeneity and its physico-chemical and kinetic properties were compared to those of the cytosolic enzyme. The molecular mass of the mitochondrial enzyme was about 54 kD, whereas that of the cytosolic enzyme was about 42 kD. The Km values of mitochondrial AFR reductase for NADH, NADPH, and AFR were higher than those of the cytosolic enzyme. Moreover, the mitochondrial enzyme proved to be less sensitive to inhibition by sulfhydryl reagents. It was concluded that the ascorbate involved in the scavenging of toxic oxygen species in potato tuber mitochondria is regenerated via the ascorbate-glutathione pathway, in which a specific AFR reductase isozyme participates.
Databáze:	OpenAIRE
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