A role for ascorbate conjugates of (+)-catechin in proanthocyanidin polymerization.
Nat Commun
; 13(1): 3425, 2022 06 14.
Article
em En
| MEDLINE
| ID: mdl-35701431
ABSTRACT
Proanthocyanidins (PAs) are natural polymers of flavan-3-ols, commonly (+)-catechin and (-)-epicatechin. However, exactly how PA oligomerization proceeds is poorly understood. Here we show, both biochemically and genetically, that ascorbate (AsA) is an alternative "starter unit" to flavan-3-ol monomers for leucocyanidin-derived (+)-catechin subunit extension in the Arabidopsis thaliana anthocyanidin synthase (ans) mutant. These (catechin)nascorbate conjugates (AsA-[C]n) also accumulate throughout the phase of active PA biosynthesis in wild-type grape flowers, berry skins and seeds. In the presence of (-)-epicatechin, AsA-[C]n can further provide monomeric or oligomeric PA extension units for non-enzymatic polymerization in vitro, and their role in vivo is inferred from analysis of relative metabolite levels in both Arabidopsis and grape. Our findings advance the knowledge of (+)-catechin-type PA extension and indicate that PA oligomerization does not necessarily proceed by sequential addition of a single extension unit. AsA-[C]n defines a new type of PA intermediate which we term "sub-PAs".
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Catequina
/
Vitis
/
Proantocianidinas
Idioma:
En
Revista:
Nat Commun
Assunto da revista:
BIOLOGIA
/
CIENCIA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
China