Pyruvate-sensitive AOX exists as a non-covalently associated dimer in the homeothermic spadix of the skunk cabbage, Symplocarpus renifolius.
The cyanide-resistant alternative oxidase (AOX) is a homodimeric protein whose activity can be regulated by the oxidation/reduction state and by alpha-keto acids. To further clarify the role of AOX in the skunk cabbage, Symplocarpus renifolius, we have performed expression and functional analyses of the encoding gene. Among the various tissues in the skunk cabbage, SrAOX transcripts were found to be specifically expressed in the thermogenic spadix. Moreover, our data demonstrate that the SrAOX protein exists as a non-covalently associated dimer in the thermogenic spadix, and is more sensitive to pyruvate than to other carboxylic acids. Our results suggest that the pyruvate-mediated modification of SrAOX activity plays a significant role in thermoregulation in the skunk cabbage.
United Graduate School of Agricultural Science, Iwate University, Ueda, Morioka, Iwate 020 8550, Japan.
Yoshihiko
Y
Onda
Yoshiaki
Y
Kato
Yukie
Y
Abe
Takanori
T
Ito
Yasuko
Y
Ito-Inaba
Miyuki
M
Morohashi
Yuka
Y
Ito
Megumi
M
Ichikawa
Kazushige
K
Matsukawa
Minoru
M
Otsuka
Hiroyuki
H
Koiwa
Kikukatsu
K
Ito
D000595:Amino Acid Sequence; D029064:Araceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D015153:Blotting, Western; D002264:Carboxylic Acids / Q000494:pharmacology; D019069:Cell Respiration / Q000187:drug effects; D003958:Diamide / Q000494:pharmacology; D019281:Dimerization; D004229:Dithiothreitol / Q000494:pharmacology; D035264:Flowers / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007656:Ketoglutaric Acids / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins; D019289:Pyruvic Acid / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013367:Submitochondrial Particles / Q000187:drug effects / Q000201:enzymology; D013696:Temperature; D000099188:Alternative Oxidase
D002264:Carboxylic Acids; D003958:Diamide; D004229:Dithiothreitol; D007656:Ketoglutaric Acids; D024101:Mitochondrial Proteins; D009243:NAD; D010088:Oxidoreductases; D010940:Plant Proteins; D019289:Pyruvic Acid; D012333:RNA, Messenger; D000099188:Alternative Oxidase