Purification and characterization of an ascorbate peroxidase from potato tuber mitochondria

Autor: Nunzio Dipierro, Silvana De Leonardis, Silvio Dipierro
Rok vydání: 2000
Předmět:
Zdroj: Plant Physiology and Biochemistry. 38:773-779
ISSN: 0981-9428
DOI: 10.1016/s0981-9428(00)01188-8
Popis: Ascorbate peroxidase (APX) has been purified from potato tuber ( Solanum tuberosum L.) mitochondria. The potato enzyme appeared to be localized inside mitochondria. The mitochondrial APX was purified to homogeneity and its physico-chemical and kinetic properties were compared with those of the cytosolic enzyme. The molecular mass of mAPX was 31 kDa, as estimated by SDS-PAGE, and was similar to that of the cytosolic enzyme, but its relative mobility in non-denaturing PAGE was different from the cytosolic APX. The K m values of mAPX for AsA and H 2 O 2 were 76.1 ± 23.1 and 80.3 ± 24.9 μM, respectively, and were higher than those of the cytosolic enzyme. Mitochondrial APX was sensitive to inhibition by sulfhydryl reagents, such as mersalyl and p-hydroxymercuribenzoate (p-HMB). A role for the mitochondrial ascorbate-ascorbate peroxidase system in the scavenging of toxic oxygen species inside potato tuber mitochondria is proposed.
Databáze: OpenAIRE
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