Article
Functional definition of the tobacco protoporphyrinogen IX oxidase substrate-binding site.
The Biochemical journal - 15 Mar 2007
Heinemann Ilka U, Diekmann Nina, Masoumi Ava, Koch Michael, Messerschmidt Albrecht, Jahn Martina, Jahn Dieter
Abstract excerpt
PPO (protoporphyrinogen IX oxidase) catalyses the flavin-dependent six-electron oxidation of protogen (protoporphyrinogen IX) to form proto (protoporphyrin IX), a crucial step in haem and chlorophyll biosynthesis. The apparent K(m) value for wild-type tobacco PPO2 (mitochondrial PPO) was 1.17 muM, with a V(max) of 4.27 muM.min(-1).mg(-1) and a catalytic activity k(cat) of 6.0 s(-1). Amino acid residues that...
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