Cloning and Characterization of Polyphenol Oxidase cDNAs of Phytolacca americana

• DOI: 10.1104/pp.107.4.1083
• Publication Date: 2002-07-27T05:01:38Z
• Authors: R. W. Joy IV; M. Sugiyama; H. Fukuda; A. Komamine
• Keywords: Transit Peptide

Two cDNA clones encoding polyphenol oxidases were isolated from a library constructed log-phase suspension culture of Phytolacca americana (pokeweed) producing betalains. The exhibit 93 and 86% sequence identity at the nucleotide deduced amino acid levels, respectively. Both contain two copper-binding domains characterized by histidine-rich regions, which are found ubiquitously in all oxidases/tyrosinases, putative third histidine-rich, region, is common to plant oxidases. One sequences contains ubiquitous transit peptide for proteins targeted internal lumen thylakoid membranes plastids considered be 98 residues length based on proposed cleavage site motif. This would produce processed approximately 54 kD. In addition features peptides, it was that an additional conserved region located between hydroxy acid-rich transfer domain. Spatial temporal expression investigated northern blot analysis total RNA various organs plants. Transcripts 2.1 2.3 kb, transcripts present only substantial levels ripening, betalain-containing fruit.