AN EFFICIENT SYNTHESIS OF PROCYANIDINS USING EQUIMOLAR CONDENSATION OF CATECHIN AND/OR EPICATECHIN CATALYZED BY YTTERBIUM TRIFLATE

Stereoselective synthesis of catechin and epicatechin dimers under intermolecular condensation of equimolar amount of catechin derivatives catalyzed by Yb(OTf)(3). The coupled products were successfully converted to procyanidins B1, B2, B3, and B4, respectively. Procyanidins B1, B2, B3, and B4 could be used as standard compounds for identifying the polyphenols in natural source.ArticleHETEROCYCLES. 79:549-563 (2009)journal articl

Evolution of substrate recognition sites (SRSs) in cytochromes P450 from Apiaceae exemplified by the CYP71AJ subfamily

Background Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as ‘blooms’, providing genetic material for the genesis and evolution of biosynthetic pathways. Furanocoumarins are allelochemicals produced by many of the species in Apiaceaous plants belonging to the Apioideae subfamily of Apiaceae and have been described as being involved in the defence reaction against phytophageous insects.[br/] Results A bloom in the cytochromes P450 CYP71AJ subfamily has been identified, showing at least 2 clades and 6 subclades within the CYP71AJ subfamily. Two of the subclades were functionally assigned to the biosynthesis of furanocoumarins. Six substrate recognition sites (SRS1-6) important for the enzymatic conversion were investigated in the described cytochromes P450 and display significant variability within the CYP71AJ subfamily. Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ.[br/] Conclusion Two subclades functionally assigned to the biosynthesis of furanocoumarins and four other subclades were identified and shown to be part of two distinct clades within the CYP71AJ subfamily. The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 ‘blooms’ in response to environmental pressures

バナナ カジツ ノ フェニルフェナレノンガタ ファイトアレキシン

京都大学0048新制・課程博士博士(農学)甲第9105号農博第1201号新制||農||828(附属図書館)学位論文||H13||N3564(農学部図書室)UT51-2001-G825京都大学大学院農学研究科応用生命科学専攻(主査)教授 大東 肇, 教授 坂田 完三, 教授 津田 盛也学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDA