Molecular cloning and characterization of a rice dehydroascorbate reductase.
Plant dehydroascorbate reductase (DHAR), which re-reduces oxidized ascorbate to maintain an appropriate level of ascorbate, is very important, but no gene or cDNA for plant DHAR has been cloned yet. Here, we describe a cDNA for a rice glutathione-dependent DHAR (designated DHAR1). A recombinant Dhar1p produced in Escherichia coli was functional. The expression sequence tag database suggests that Dhar1p homologs exist in various plants. Furthermore, the rice Dhar1p has a low similarity to rat DHAR, although the rice enzyme has a considerably higher specific activity than the mammalian one. The mRNA level of DHAR1, the protein level of Dhar1p and the DHAR activity in rice seedlings were elevated by high temperature, suggesting the protection role of DHAR at high temperature.
Urano
J
J
Department of Biology, Faculty of Science, Shizuoka University, Shizuoka, Japan.
Nakagawa
T
T
Maki
Y
Y
Masumura
T
T
Tanaka
K
K
Murata
N
N
Ushimaru
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D017343:Genes, Plant; D006358:Hot Temperature; D006801:Humans; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics*; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D018744:DNA, Plant; D012333:RNA, Messenger; D018749:RNA, Plant; D011994:Recombinant Proteins; D010088:Oxidoreductases; C020666:glutathione dehydrogenase (ascorbate)