RRC ID 30972
Author Saito S, Motawia MS, Olsen CE, Møller BL, Bak S.
Title Biosynthesis of rhodiocyanosides in Lotus japonicus: rhodiocyanoside A is synthesized from (Z)-2-methylbutanaloxime via 2-methyl-2-butenenitrile.
Journal Phytochemistry
Abstract Lotus japonicus contains the two cyanogenic glucosides, linamarin and lotaustralin, and the non cyanogenic hydroxynitriles, rhodiocyanoside A and D, with rhodiocyanoside A as the major rhodiocyanoside. Rhodiocyanosides are structurally related to cyanogenic glucosides but are not cyanogenic. In vitro administration of intermediates of the lotaustralin pathway to microsomes prepared from selected L. japonicus accessions identified 2-methyl-2-butenenitrile as an intermediate in the rhodiocyanoside biosynthetic pathway. In vitro inhibitory studies with carbon monoxide and tetcyclacis indicate that the conversion of (Z)-2-methylbutanal oxime to 2-methyl-2-butenenitrile is catalyzed by cytochrome P450(s). Carbon monoxide inhibited cyanogenic glucosides as well as rhodiocyanosides synthesis, but inhibition of the latter pathway was much stronger. These results demonstrate that the cyanogenic glucoside and rhodiocyanosides pathways share CYP79Ds to obtain (Z)-2-methylbutanaloxime from l-isoleucine, whereas the subsequent conversions are catalyzed by different P450s. The aglycon of rhodiocyanoside A forms the cyclic product 3-methyl-2(5H)-furanone. Furanones are known to possess antimicrobial properties indicating that rhodiocyanoside A may have evolved to serve as a phytoanticipin that following β-glucosidase activation and cyclization of the aglycone formed, give rise to a potent defense compound.
Volume 77
Pages 260-7
Published 2012-5
DOI 10.1016/j.phytochem.2012.01.020
PII S0031-9422(12)00049-0
PMID 22385904
MeSH Biosynthetic Pathways Cytochrome P-450 Enzyme System / genetics Cytochrome P-450 Enzyme System / metabolism Cytochrome P-450 Enzyme System / physiology Glucosides / biosynthesis* Glucosides / chemistry Glucosides / metabolism Glycosides / biosynthesis* Loteae / genetics Loteae / metabolism* Nitriles / chemistry* Nitriles / metabolism Oximes / chemistry* Oximes / metabolism
IF 2.905
Times Cited 18
Lotus / Glycine Gifu B-129