Biosynthesis of bioactive tamarixetin in recombinant Escherichia coli.

Tamarixetin, a monomethylated derivative of quercetin, has been reported to possess many important biological activities. In the present study, a whole cell biotransformation system was used for regiospecific methylation of quercetin to produce 4'-O-methylated quercetin (tamarixetin) using methyltransferase from Streptomyces sp. KCTC 0041BP in Escherichia coli Bl21 (DE3).

Combinatorial approach for improved cyanidin 3-O-glucoside production in Escherichia coli.

Background: Multi-monocistronic and multi-variate vectors were designed, built, and tested for the improved production of cyanidin 3-O-glucoside (C3G) in Escherichia coli BL21 (DE3). The synthetic bio-parts were designed in such a way that multiple genes can be assembled using the bio-brick system, and expressed under different promoters in a single vector. The vectors harbor compatible cloning sites, so that the genes can be shuffled from one vector to another in a single step, and assembled into a single vector.

One-Pot Multienzyme Cofactors Recycling (OPME-CR) System for Lactose and Non-natural Saccharide Conjugated Polyphenol Production.

A one-pot multienzyme cofactors recycling (OPME-CR) system was designed for the synthesis of UDP-α-d-galactose, which was combined with LgtB, a β-(1,4) galactosyltransferase from Neisseria meningitidis, to modify various polyphenol glycosides. This system recycles one mole of ADP and one mole of UDP to regenerate one mole of UDP-α-d-galactose by consuming two moles of acetylphosphate and one mole of d-galactose in each cycle. The ATP additionally used to generate UDP from UMP was also recycled at the beginning of the reaction.

Enzymatic synthesis of novel quercetin sialyllactoside derivatives.

Quercetin and its derivatives are important flavonols that show diverse biological activity, such as antioxidant, anticarcinogenic, anti-inflammatory, and antiviral activities. Adding different substituents to quercetin may change the biochemical activity and bioavailability of molecules, when compared to the aglycone. Here, we have synthesised two novel derivatives of quercetin, quercetin-3---d-glucopyranosyl, 4''--d-galactopyranosyl 3'''----acetyl neuraminic acid i.

Characterization of regioselective flavonoid O-methyltransferase from the Streptomyces sp. KCTC 0041BP.

A flavonoid comprises polyphenol compounds with pronounced antiviral, antioxidant, anticarcinogenic, and anti-inflammatory effects. The flavonoid modification by methylation provides a greater stability and improved pharmacokinetic properties. The methyltransferase from plants or microorganisms is responsible for such substrate modifications in a regiospecific or a promiscuous manner.