Glycosides, biosynthesis

Lewinsohn E, Britsch L, Mazur Y, Gressel J (1989) Flavanone glycoside biosynthesis in Citrus chalcone synthase, UDP-glucose flavanone-7-0-glucosy-transferase and -rhamnosyltransferase activities in cell-free extracts. Plant Physiol 91 1321-1328... 

Jones, P. et al., UGT73C6 and UGT78D1 — glycosyltransferases involved in fiavonol glycoside biosynthesis in Arabidopsis thaliana. J. Biol. Chem., 278, 43910, 2003. 

Seidel, S., Kreis, W. and Reinhard, E. (1990) A5-3fJ-Hydroxysteroid dehydrogenase/ A5-A4-ketosteroid isomerase (3fJ-HSD) a possible enzyme of cardiac glycoside biosynthesis, in cell cultures and plants of Digitalis lanata EHRH. Plant Cell Rep., 8, 621-4. 

Another series of noncyanogenic nitrile glycosides, with structural similarities to intermediates in cyanogenic glycoside biosynthesis are found in members of the Aquifoliaceae, Boraginaceae, Crassulaceae, Menispermaceae, Fabaceae, Ranunculaceae, and Simmondsiaceae (Fig. 16.19) (Seigler, 1991). 

Jones P, Messner B, Nakajima J et al (2003) UGT73C6 and UGT78D1, glycosyltransferases involved in flavonol glycoside biosynthesis in Arabidopsis thaliana. J Biol Chem 278 43910 3918... 

Ruddat M, Heftmann E, Lang A (1965) Steviol glycoside biosynthesis. Arch Biochem Bio-phys 110(3) 496 99... 

Flavonols are the widest spread metabolites in higher plants and predominantly accumulate as glycosides. In vitro biochemical analyses and in planta metabolite profiling have identified a number of interesting Arabidopsis GTs involved in flavonol glycoside biosynthesis, such as UGT78D1 and UGT89C1 which catalyze the 3-OH and 7-OH rhamnosylation of flavonols... 

Glycolysis, 903-904, 1143-1150 overall result of, 1150 steps in, 1143-1145 Glycoprotein, 991 biosynthesis of, 991 Glycoside, 989... 

Nakagawa, M. and N. Misawa. 1991. Analysis of carotenoid glycosides produced in gram-negative bacteria by introduction of the Erwinia uredovora carotenoid biosynthesis genes. Agric. Biol. Chem. 55 2147-2148. 

A recent example demonstrates that corals rely on induced biosynthesis of terpenes as a dynamic defense strategy as well. The induction of terpenoid secondary metabolites was observed in the sea whip Pseudopterogorgia elisabethae [162]. Levels of pseudopterosins 89-92, a group of diterpene glycosides with anti-inflammatory and analgesic properties (Scheme 23) [163-165], are increased in response predation by the mollusk Cyphoma gibbosum. First bioassays indicate that these natural products are involved in the chemical defense. 

Clearly, in biosynthesis the ketoses play a major role as active intermediates in the intertransformation of monosaccharides and as precursors of aldoses which usually appear as stable end-products and are stored in the form of polysaccharide or glycosides. An exception is the novel D-glu-... 

A common intermediate for all the nucleotides is 5-phosphoribosyl-l-diphosphate (PRPP), produced by successive ATP-dependent phosphorylations of ribose. This has an a-diphosphate leaving group that can be displaced in Sn2 reactions. Similar Sn2 reactions have been seen in glycoside synthesis (see Section 12.4) and biosynthesis (see Box 12.4), and for the synthesis of aminosugars (see Section 12.9). For pyrimidine nucleotide biosynthesis, the nucleophile is the 1-nitrogen of uracil-6-carboxylic acid, usually called orotic acid. The product is the nucleotide orotidylic acid, which is subsequently decarboxylated to the now recognizable uridylic acid (UMP). 

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