Plastid terminal oxidase

Plastid terminal oxidase or plastoquinol terminal oxidase (PTOX) is an enzyme that resides on the thylakoid membranes of plant and algae chloroplasts and on the membranes of cyanobacteria. The enzyme was hypothesized to exist as a photosynthetic oxidase in 1982 and was verified by sequence similarity to the mitochondrial alternative oxidase (AOX).[1] The two oxidases evolved from a common ancestral protein in prokaryotes, and they are so functionally and structurally similar that a thylakoid-localized AOX can restore the function of a PTOX knockout.[2]

  1. ^ McDonald AE, Ivanov AG, Bode R, Maxwell DP, Rodermel SR, Hüner NP (August 2011). "Flexibility in photosynthetic electron transport: the physiological role of plastoquinol terminal oxidase (PTOX)". Biochim. Biophys. Acta. 1807 (8): 954–67. doi:10.1016/j.bbabio.2010.10.024. PMID 21056542.
  2. ^ Fu A, Liu H, Yu F, Kambakam S, Luan S, Rodermel S (April 2012). "Alternative oxidases (AOX1a and AOX2) can functionally substitute for plastid terminal oxidase in Arabidopsis chloroplasts". Plant Cell. 24 (4): 1579–95. doi:10.1105/tpc.112.096701. PMC 3398565. PMID 22534126.