Nicotinate riboside salvage in plants: presence of nicotinate riboside kinase in mungbean seedlings.
Salvage of nicotinate riboside for NAD synthesis was investigated in mungbean seedlings. Nicotinate riboside kinase activity was detected in extracts from cotyledons. Exogenously supplied [carboxyl-(14)C]nicotinate riboside was readily converted into pyridine nucleotides in cotyledons of mungbean seedlings. This conversion was also found in embryonic axes, but the rate was lower than in cotyledons. These results suggest that, in addition to the seven-component pyridine nucleotide cycle (PNC VII), an eight-component cycle (PNC VIII) involving nicotinate riboside kinase operates in plants.
Department of Biological Sciences, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, Japan.
Ayu
A
Matsui
Hiroshi
H
Ashihara
D018548:Cotyledon / Q000201:enzymology; D007887:Fabaceae / Q000201:enzymology*; D009243:NAD / Q000096:biosynthesis*; D010770:Phosphotransferases / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D012263:Ribonucleosides / Q000378:metabolism*; D036226:Seedlings / Q000201:enzymology
D010940:Plant Proteins; D012263:Ribonucleosides; D009243:NAD; C030285:nicotinic acid ribonucleoside; D010770:Phosphotransferases