Metabolism of chiral ionylideneacetic acids on the abscisic acid biosynthetic pathway in Cercospora.
A Chiralcel OJ column was used to determine the absolute configuration of naturally occurring alpha-ionylideneacetic acid from Cercospora rosicola and gamma-ionylideneacetic acid from C. cruenta as (R) enantiomers in accordance with their biosynthetic product, (S)-ABA. Both enantiomers of [1, 2-(13)C2]-alpha and gamma-ionylideneacetic acids were prepared and fed to C. rosicola and C. cruenta. Six combinations of feeding experiments comparatively and unequivocally demonstrated stereoselectivity in the biosynthetic conversions, including stepwise hydroxylation at C-1' and 4'. Enzymatic isomerization from the gamma to alpha-intermediate was suggested not to be involved in ABA biosynthesis in C. rosicola.
Yamamoto
H
H
Faculty of Agriculture, Niigata University, Ikarashi, Japan. hirotaka@agr.niigata-u.ac.jp
Inomata
M
M
Tsuchiya
S
S
Nakamura
M
M
Oritani
T
T
D000040:Abscisic Acid / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000737:chemistry* / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D003904:Mitosporic Fungi / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D013237:Stereoisomerism; D013379:Substrate Specificity; D013831:Thiamine / Q000378:metabolism
D010710:Phosphates; C425560:alpha-ionylideneacetic acid; C425561:gamma-ionylideneacetic acid; D018698:Glutamic Acid; D000040:Abscisic Acid; D013831:Thiamine