Isolation of DOPA 4,5-dioxygenase homologs from betalain non-producing plants.

Abstract

It is an important problem that why do the two pigment anthocyanin and betacyanin never occur together in the same plant. DOPA 4,5-dioxygenase (DOD) is an important enzyme to synthesize betalain pigment in higher plant. However, it is known that DOD homologs exist in the genome of betalain non-producing plants. To analyze the difference between the DOD of betalain producing plant and betalain non-producing plants contribute to elucidate the problem. We cloned DOD homolog cDNAs from arabidopsis, torenia and carnation. Each recombinant protein extracted from Escherichia coli harboring these cDNA were added to a reaction mixture containing L-DOPA. When recombinant tereina DOD was added to the reaction mixture, the mixture color turned to yellow and and a reaction product in the mixture was betalamic acid confirmed by HPLC.