caa a22 4500 477100104 CHVBK 20180405111538.0 cr unu---uuuuu 170330e19961101xx s 000 0 eng 10.1007/BF00200299 doi (NATIONALLICENCE)springer-10.1007/BF00200299 Stereoselectivity in the biosynthetic conversion of xanthoxin into abscisic acid [Elektronische Daten] [Hiroshi Yamomoto, Takayuki Oritani] All stereoisomers of xanthoxin (XAN) and abscisic aldehyde (ABA-aldehyde) were prepared from (R) and (S)-4-hydroxy-β-cyclogeraniol via asymmetric epoxidation. Their stomatal closure activities were measured on epidermal strips of Commelina communis L. Natural (S)-ABA-aldehyde showed strong activity comparable to that of (S)-abscisic acid (ABA). Natural (1′S, 2′R, 4′S)XAN and (1′S, 2′R, 4′R)-epi-XAN also induced stomatal closure at high concentrations. On the other hand, unnatural (1′R)-enantiomers of XAN, epi-XAN, and ABA-aldehyde were not effective. To further examine the Stereoselectivity on the biosynthetic pathway to ABA, deuterium-labeled substrates were prepared and fed to Lycopersicon esculentum Mill, under non-stressed or water-stressed conditions. Substantial incorporations into ABA were observed in the cases of natural (1′S, 2′R, 4′S)-XAN, (1′S, 2′R, 4′R)-epi-XAN and both enantiomers of ABA-aldehyde, leading to the following conclusions. The negligible effect of unnatural (1′R)-enantiomers of XAN, epi-XAN and ABA-aldehyde can be explained by their own biological inactivity and/or their conversion to inactive (R)-ABA. Even in the isolated epidermal strips, putative aldehyde oxidase activity is apparently sufficient to convert ABA-aldehyde to ABA while the activity of XAN dehydrogenase seems very weak. The stereochemistry of the 1′, 2′-epoxide is very important for the XAN-dehydrogenase while this enzyme is less selective regarding the 4′-hydrdxyl group of XAN and converts both (1′S, 2′R, 4′S)-XAN and (1′S, 2′R, 4′R)-epi-XAN to (S)-ABA-aldehyde. Abscisic aldehyde oxidase can nonstereoselectively convert both (S) and (R)-ABA-aldehyde to biologically active (S) and inactive (R)-ABA, respectively. Springer-Verlag, 1996 Abscisic acid biosynthesis nationallicence Abscisic aldehyde nationallicence Chiral synthesis nationallicence Epi-xanthoxin nationallicence Stomatal closure nationallicence Xanthoxin nationallicence ABA : abscisic acid nationallicence ABA-aldehyde : abscisic aldehyde nationallicence DET : diethyl tartrate nationallicence epi -XAN : xanthoxin epimer nationallicence FCC : flash column chromatography nationallicence GC-EI-MS : gas chromatography-electron impact-mass spectrometry nationallicence MeABA : abscisic acid methyl ester nationallicence IR : infrared nationallicence NMR : nuclear magnetic resonance nationallicence PCC : pyridinium chlorochromate nationallicence THF : tetrahydrofuran nationallicence XAN : xanthoxin nationallicence Yamomoto Hiroshi Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, 1-1 Tsutumidori-Amamiyamachi, Aoba-ku, 981, Sendai, Japan aut Oritani Takayuki Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, 1-1 Tsutumidori-Amamiyamachi, Aoba-ku, 981, Sendai, Japan aut Planta Springer-Verlag 200/3(1996-11-01), 319-325 0032-0935 200:3<319 1996 200 425 https://doi.org/10.1007/BF00200299 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00200299 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yamomoto Hiroshi Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, 1-1 Tsutumidori-Amamiyamachi, Aoba-ku, 981, Sendai, Japan aut NATIONALLICENCE 700 1- Oritani Takayuki Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, 1-1 Tsutumidori-Amamiyamachi, Aoba-ku, 981, Sendai, Japan aut NATIONALLICENCE 773 0- Planta Springer-Verlag 200/3(1996-11-01), 319-325 0032-0935 200:3<319 1996 200 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer