Flavonoid Biotechnology – New Ways to High‐Added‐Value Compounds

Pavlidis, Ioannis V.; Gall, Mechthild; Geißler, Torsten; Gross, Egon; Bornscheuer, Uwe T.

doi:10.1002/9783527677122.ch9

Cited by 1 publication

(1 citation statement)

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“…Dihydrochalcones are structurally related to chalcones, and we previously showed that they are accepted as substrates by both CH3H and F3′H of the ornamental plant Cosmos sulphureus , albeit to a low extent [ 15 ]. Recent years saw increasing interest in the metabolic engineering of the dihydrochalcone pathway in various microorganisms to specifically produce dihydrochalcones for nutritional or pharmaceutical purposes [ 26 , 27 , 28 ]. Thus, the enzymes and genes involved in the dihydrochalcone pathway of apples are also of biotechnological interest.…”

Section: Introductionmentioning

confidence: 99%

Molecular and Enzymatic Characterization of Flavonoid 3′-Hydroxylase of Malus × domestica

Weissensteiner

Molitor

Marinovic

et al. 2021

Plants

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Malus × domestica (apple) accumulates particularly high amounts of dihydrochalcones in various tissues, with phloridzin (phloretin 2′-O-glucoside) being prevalent, although small amounts of 3-hydroxyphloretin and 3-hydroxyphloridzin are also constitutively present. The latter was shown to correlate with increased disease resistance of transgenic M. × domestica plants. Two types of enzymes could be involved in 3-hydroxylation of dihydrochalcones: polyphenol oxidases or the flavonoid 3′-hydroxylase (F3′H), which catalyzes B-ring hydroxylation of flavonoids. We isolated two F3′H cDNA clones from apple leaves and tested recombinant Malus F3′Hs for their substrate specificity. From the two isolated cDNA clones, only F3′HII encoded a functionally active enzyme. In the F3′HI sequence, we identified two putatively relevant amino acids that were exchanged in comparison to that of a previously published F3′HI. Site directed mutagenesis, which exchanged an isoleucine into methionine in position 211 restored the functional activity, which is probably because it is located in an area involved in interaction with the substrate. In contrast to high activity with various flavonoid substrates, the recombinant enzymes did not accept phloretin under assay conditions, making an involvement in the dihydrochalcone biosynthesis unlikely.

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Section: Introductionmentioning

confidence: 99%