English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Tea ( Camellia sinensis  (L.) O. Kuntze) leaves are a major source of flavonoids that mainly belong to the flavan 3-ols or catechins. Apart from being responsible for tea quality, these compounds have medicinal properties. Flavanone 3-hydroxylase (F3H) is an abundant enzyme in tea leaves that catalyzes the stereospecific hydroxylation of (2 S )-naringenin to form (2 R ,3 R )-dihydrokaempferol. We report a full-length cDNA sequence of  F3H  from tea ( CsF3H  Accession no. AY641730).  CsF3H  comprised 1365 bp with an open reading frame of 1107 nt (from 43 to 1149) encoding a polypeptide of 368 amino acids. Expression of  CsF3H  in an expression vector in  Escherichia coli  yielded a functional protein with a specific activity of 32 nmol min −1  mg protein −1 . There was a positive correlation between the concentration of catechins and  CsF3H  expression in leaves of different developmental stages.  CsF3H  expression was down-regulated in response to drought, abscisic acid and gibberellic acid treatment, but up-regulated in response to wounding. The concentration of catechins paralleled the expression data. Exposure of tea shoots to 50−100 μM catechins led to down-regulation of  CsF3H  expression suggesting substrate mediated feedback regulation of the gene. The strong correlation between the concentration of catechins and  CsF3H  expression indicates a critical role of F3H in catechin biosynthesis.

tree physiology

An early gene of the flavonoid pathway, flavanone 3-hydroxylase, exhibits a positive relationship with the concentration of catechins in tea ( Camellia sinensis )