A role for ascorbate conjugates of (+)-catechin in proanthocyanidin polymerization.

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)_n:ascorbate 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

SUBMITTER: Yu K 

PROVIDER: S-EPMC9197940 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature