Synthesis of Uridine 5′-(α-D-Fucopyranosyl Diphosphate) and (Digitoxigenin-3β-yl)-β-D-Fucopyranoside and Enzymatic β-D-Fucosylation of Cardenolide Aglycones in Digitalis lanata1

Faust, T.; Theurer, Christoph P.; Eger, Kurt; Kreis, Wolfgang

doi:10.1006/bioo.1994.1012

Cited by 10 publications

(6 citation statements)

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“…3), the 4'-epimer of 25, which is a minor glycoside in D. lanata (1). When UPDF was preincubated with the enzyme extract before adding 13, the cardenolides 25 and 27 were produced in almost equal amounts, indicating that the sugar is modified at the sugar nucleotide level and not at the glycoside stage and that DQT must be active in these extracts (66). Neither DQT nor epimerase activity were present in the partially purified DFT preparation (see above).…”

Section: Udp-quinovose:digitoxigenin 3-o-quinovosyltransferase mentioning

confidence: 98%

“…The DET catalyzes the transfer of the sugar moiety of UDP-a-D-fucose to a cardenolide aglycone, such as 13 or 23 (66) ( Fig.3). Compound 25, the product formed in the presence of 13 is a minor glycoside in D. lanata (1).…”

Section: Udp-fucose:digitoxigenin 3-o-fucosyltransferase (Dft)mentioning

confidence: 99%

“…Glucodigifucoside (26) was formed upon incubation at 37 °C and pH 5.7 of a soluble enzyme preparation from young leaves of D. lanata in the presence of UDP-a-n-glucose and 25 (66) (Fig.3). The enzyme is not identical with the glucosyltransferases described above, but has not been characterized in detail as yet.…”

Section: Udp-glucose:digiproside 4'-o-glucosyltransferase (Dpgt)mentioning

confidence: 99%

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Cardenolide Biosynthesis in Foxglove¹

Kreis¹,

Hensel²,

Stuhlemmer³

1998

Planta Med

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The article reviews the state of knowledge on the biosynthesis of cardenolides in the genus Digitalis. It summarizes studies with labelled and unlabelled precursors leading to the formulation of the putative cardenolide pathway. Alternative pathways of cardenolide biosynthesis are discussed as well. Special emphasis is laid on enzymes involved in either pregnane metabolism or the modification of cardenolides.About 20 enzymes which are probably involved in cardenolide formation have been described "downstream" of cholesterol, including various reductases, oxido-reductases, glycosyl transferases and glycosidases as well as acyl transferases, acyl esterases and P450 enzymes. Evidence is accumulating that cardenolides are not assembled on one straight conveyor belt but instead are formed via a complex multidimensional metabolic grid. For example "fucose-type" cardenolides and "digitoxosetype" cardenolides seem to form via different biosynthetic branches and the "norcholanic acid pathway" identified recently seems to be operative only in the formation of fucosetype cardenolides.

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Section: Udp-quinovose:digitoxigenin 3-o-quinovosyltransferase mentioning

confidence: 98%

Section: Udp-fucose:digitoxigenin 3-o-fucosyltransferase (Dft)mentioning

confidence: 99%

Section: Udp-glucose:digiproside 4'-o-glucosyltransferase (Dpgt)mentioning

confidence: 99%

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Cardenolide Biosynthesis in Foxglove¹

Kreis¹,

Hensel²,

Stuhlemmer³

1998

Planta Med

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“…As strong USPase knock-down had no changes in cell wall nor leaf soluble fucose content ( Geserick and Tenhaken, 2013a ), UDP-α- D -Fuc may not be a key player in fucose cycling or cell wall formation, but perhaps may be involved in secondary metabolism. Addition of a synthetically prepared UDP-α- D -Fuc to leaf extracts was reported to lead to incorporation of the Fuc molecule to cardenolide aglycones, a group of secondary metabolites ( Faust et al, 1994 ), but the resulting compounds were β- D -fucosylated rather than α- D -fucosylated, suggesting the involvement of an inverting-type of a glycosyltrasferase. Plants contain many such glycosyltransferases ( Lairson et al, 2008 ), but to our knowledge none has yet been identified which carries the inversion when using UDP-α- D -Fuc as a substrate.…”

Section: Discussionmentioning

confidence: 99%

Substrate Specificity and Inhibitor Sensitivity of Plant UDP-Sugar Producing Pyrophosphorylases

Decker

Kleczkowski

2017

Front. Plant Sci.

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UDP-sugars are essential precursors for glycosylation reactions producing cell wall polysaccharides, sucrose, glycoproteins, glycolipids, etc. Primary mechanisms of UDP sugar formation involve the action of at least three distinct pyrophosphorylases using UTP and sugar-1-P as substrates. Here, substrate specificities of barley and Arabidopsis (two isozymes) UDP-glucose pyrophosphorylases (UGPase), Arabidopsis UDP-sugar pyrophosphorylase (USPase) and Arabidopsis UDP-N-acetyl glucosamine pyrophosphorylase2 (UAGPase2) were investigated using a range of sugar-1-phosphates and nucleoside-triphosphates as substrates. Whereas all the enzymes preferentially used UTP as nucleotide donor, they differed in their specificity for sugar-1-P. UGPases had high activity with D-Glc-1-P, but could also react with Fru-1-P and Fru-2-P (Km values over 10 mM). Contrary to an earlier report, their activity with Gal-1-P was extremely low. USPase reacted with a range of sugar-1-phosphates, including D-Glc-1-P, D-Gal-1-P, D-GalA-1-P (Km of 1.3 mM), β-L-Ara-1-P and α-D-Fuc-1-P (Km of 3.4 mM), but not β-L-Fuc-1-P. In contrast, UAGPase2 reacted only with D-GlcNAc-1-P, D-GalNAc-1-P (Km of 1 mM) and, to some extent, D-Glc-1-P (Km of 3.2 mM). Generally, different conformations/substituents at C2, C4, and C5 of the pyranose ring of a sugar were crucial determinants of substrate specificity of a given pyrophosphorylase. Homology models of UDP-sugar binding to UGPase, USPase and UAGPase2 revealed more common amino acids for UDP binding than for sugar binding, reflecting differences in substrate specificity of these proteins. UAGPase2 was inhibited by a salicylate derivative that was earlier shown to affect UGPase and USPase activities, consistent with a common structural architecture of the three pyrophosphorylases. The results are discussed with respect to the role of the pyrophosphorylases in sugar activation for glycosylated end-products.

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“…181 A crude enzyme preparation from the young leaves of Digitalis lanata EHRH was shown to catalyse the transfer of D-fucose from synthetic UDP-a-D-fucose to cardenolide aglycons such as digitoxigenin (Scheme 110). 182 Uridine 5 Similarly, in a regioselective synthesis, the galactosyl derivatives of stevioside and steviolbioside were afforded in good yields (Scheme 113). 185 On the other hand, it is also possible to transform natural steroidal glycosides by enzymatic degradation procedures and natural saponins having terminal b-D-glucopyranose were treated with b-glucosidase, yielding the corresponding hydrolysed compounds (Scheme 114).…”

Section: Enzymatic Methodsmentioning

confidence: 99%

The glycosylation of steroids

Pellissier

2004

Tetrahedron

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Synthesis of Uridine 5′-(α-D-Fucopyranosyl Diphosphate) and (Digitoxigenin-3β-yl)-β-D-Fucopyranoside and Enzymatic β-D-Fucosylation of Cardenolide Aglycones in Digitalis lanata1

Cited by 10 publications

References 0 publications

Cardenolide Biosynthesis in Foxglove¹

Cardenolide Biosynthesis in Foxglove¹

Substrate Specificity and Inhibitor Sensitivity of Plant UDP-Sugar Producing Pyrophosphorylases

The glycosylation of steroids

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Synthesis of Uridine 5′-(α-D-Fucopyranosyl Diphosphate) and (Digitoxigenin-3β-yl)-β-D-Fucopyranoside and Enzymatic β-D-Fucosylation of Cardenolide Aglycones in Digitalis lanata1

Cited by 10 publications

References 0 publications

Cardenolide Biosynthesis in Foxglove1

Cardenolide Biosynthesis in Foxglove1

Substrate Specificity and Inhibitor Sensitivity of Plant UDP-Sugar Producing Pyrophosphorylases

The glycosylation of steroids

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Product

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Cardenolide Biosynthesis in Foxglove¹

Cardenolide Biosynthesis in Foxglove¹