Alternative system of succinate oxidation in glyoxysomes of higher plants

FEBS Letters

Popov, V.N¹  Falaleeva, M.I¹  Igamberdiev, A.U¹ 

[1] Department of Plant Physiology and Biochemistry, Voronezh State University, Voronezh 394693, Russian Federation

关键词: Glyoxysomal succinate oxidase;    Succinate dehydrogenase;    Zea mays;   

DOI  :  10.1016/0014-5793(95)00563-O

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Succinate oxidation in scutella of germinating seeds of wheat and maize was investigated. Besides oxidation via succinate dehydrogenase (SDH; EC 1.3.99.1), an alternative path of succinate oxidation insensitive to SDH inhibitors — malonate and thenoyltrifluoroacetone (TTFA) — was revealed. Using isopicnic sucrose gradient it was shown that this path is localized in glyoxysomal membranes. Glyoxysomal succinate oxidase (GSO) converts succinate directly into malate with the production of hydrogen peroxide identified using auxilary enzymes malate dehydrogenase and peroxidase. GSO is most active during the intensive operation of the glyoxylate cycle (3–5 days of germination). Quinacrine, the inhibitor of flavine-containing oxidases, strongly suppressed the activity of GSO. K _m for succinate is 18 mM for GSO from maize scutellum. It is concluded that in scutella of cereal seeds the glyoxysomal succinate oxidation non-linked with ATP synthesis operates.

【 授权许可】

Unknown