This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: raffinose biosynthesis
|Superclasses:||Biosynthesis → Carbohydrates Biosynthesis → Oligosaccharides Biosynthesis|
Some taxa known to possess this pathway include : Arabidopsis thaliana col, Cucurbita pepo, Glycine max, Lens culinaris, Phaseolus vulgaris, Pisum sativum, Solanum lycopersicum, Vicia faba, Vigna angularis
Expected Taxonomic Range: Magnoliophyta
Stachyose and raffinose are two members of the so-called 'raffinose series' of sucrosyl oligosaccharides (also known as raffinose family oligosaccharides, RFOs). Sucrosyl oligosaccharides represent a large portion of primary oligosaccharides in plants (defined as oligosaccharides synthesized by the action of a glycosyl transferase that mediates the transfer of a glycopyranosyl residue to either the glucopyranosyl or fructofuranosyl moiety of sucrose). They are differentiated from secondary oligosaccharides which are generated by the hydrolysis of higher oligosaccharides, polysaccharides or heterosides. For review, see [Kandler82]). Members of the raffinose series occur at least in traces in each plant family; it is one of the most widespread sucrosyl oligosaccharide series in flowering plants and might even be ubiquitous (see [Kandler82] for review). This series comprises raffinose, stachyose, verbascose, ajugose (see also ajugose biosynthesis I (galactinol-dependent)) as well as several other compounds with a higher degree of polymerization (DP; the highest is a nonasaccharide; none of these higher-DP oligosaccharides in the series have not yet been named). The sugars of this series consist of α1,6-linked chains of D-galactose attached to the 6-glucosyl position of sucrose. They are synthesized in leaves, roots and tubers. Raffinose is usually found in all parts of the plants including seeds, unless another sucrosyl oligosaccharide series prevails. Stachyose is often the main oligosaccharide in storage organs although variations occur between species. Functionally, these soluble carbohydrates are used for carbon transport and storage by the plant, although they have also been reported as possibly acting as protective agents during maturation of drying seeds [Horbowicz94] and during cold stress [Travert97, Gilmour00]. Sugars of this series have long been considered as undesirable non-digestible factors that promote flatulence. Recently, however, it has been suggested that they might have beneficial effects on the gut microflora [Tortuero97]. Moreover, they have been suggested for non-food applications (organ preservation) [Fischer01a].
Enzymes of the pathway: The first step of the biosynthesis starts with the formation of the unusual galactosyl donor galactinol. The enzyme allowing the formation of this compound is galactinol synthase, which catalyzes the transfer of a galactosyl residue from UDP-galactose onto myo-inositol [UDP-galactose:myo-inositol (1-α-D) galactosyltransferase]. Several enzymes with this activity have been characterized and purified. The only known function of galactinol is in the biosynthesis of RFOs; it has therefore been postulated that galactinol synthase might be the committed and regulatory step for the synthesis of these compounds. The following step consists in the transfer of galactosyl units from galactinol to sucrose to form raffinose, the first RFO of the series. The enzyme catalyzing this reaction is known as raffinose synthase (galactinol:sucrose 6-galactosyltransferase). Stachyose is formed by the additional incorporation of a galactosyl unit to raffinose by a stachyose synthase (galactinol:raffinose 6-galactosyltransferase).
Unification Links: AraCyc:PWY-5337
Bentsink00: Bentsink L, Alonso-Blanco C, Vreugdenhil D, Tesnier K, Groot SP, Koornneef M (2000). "Genetic analysis of seed-soluble oligosaccharides in relation to seed storability of Arabidopsis." Plant Physiol 124(4);1595-604. PMID: 11115877
Fischer01a: Fischer S, Hopkinson D, Liu M, MacLean AA, Edwards V, Cutz E, Keshavjee S (2001). "Raffinose improves 24-hour lung preservation in low potassium dextran glucose solution: a histologic and ultrastructural analysis." Ann Thorac Surg 71(4);1140-5. PMID: 11308150
Gilmour00: Gilmour SJ, Sebolt AM, Salazar MP, Everard JD, Thomashow MF (2000). "Overexpression of the Arabidopsis CBF3 transcriptional activator mimics multiple biochemical changes associated with cold acclimation." Plant Physiol 124(4);1854-65. PMID: 11115899
Hoch99: Hoch G, Peterbauer T, Richter A (1999). "Purification and characterization of stachyose synthase from lentil (Lens culinaris) seeds: galactopinitol and stachyose synthesis." Arch Biochem Biophys 366(1);75-81. PMID: 10334866
Horbowicz94: Horbowicz M., Obendorf R.L. (1994). "Seed dessication tolerance and storability: dependence on flatulence-producing oligosaccharides and cyclitols - review and survey." Seed Sci. Res. 4:835-405.
Kandler82: Kandler O., Hopf H. (1982). "Oligosaccharides based on sucrose (sucrosyl oligosaccharides)." In Plant Carbohydrates I- Intracellular carbohydrates, Encyclopedia of plant physiology New Series Vol 13A, Springer-Verlag eds. Chapter 8. pp. 348.
Travert97: Travert S, Valerio L, Fouraste I, Boudet AM, Teulieres C (1997). "Enrichment in Specific Soluble Sugars of Two Eucalyptus Cell-Suspension Cultures by Various Treatments Enhances Their Frost Tolerance via a Noncolligative Mechanism." Plant Physiol 114(4);1433-1442. PMID: 12223781
Zuther04: Zuther E, Buchel K, Hundertmark M, Stitt M, Hincha DK, Heyer AG (2004). "The role of raffinose in the cold acclimation response of Arabidopsis thaliana." FEBS Lett 576(1-2);169-73. PMID: 15474032
But13: But SY, Khmelenina VN, Reshetnikov AS, Trotsenko YA (2013). "Bifunctional sucrose phosphate synthase/phosphatase is involved in the sucrose biosynthesis by Methylobacillus flagellatus KT." FEMS Microbiol Lett. PMID: 23865613
But13a: But SIu, Khmelina VN, Mustakhimova II, Trotsenko IuA (2013). "[Production and characterization of Methylomicrobium alcaliphilum 20Z knockout mutants, which has sucrose and ectoin synthesis defective genes]." Mikrobiologiia 82(2);251-3. PMID: 23808151
But15: But SY, Khmelenina VN, Reshetnikov AS, Mustakhimov II, Kalyuzhnaya MG, Trotsenko YA (2015). "Sucrose metabolism in halotolerant methanotroph Methylomicrobium alcaliphilum 20Z." Arch Microbiol. PMID: 25577257
Doronina03: Doronina N, Darmaeva T, Trotsenko Y (2003). "Methylophaga natronica sp. nov., a new alkaliphilic and moderately halophilic, restricted-facultatively methylotrophic bacterium from soda lake of the Southern Transbaikal region." Syst Appl Microbiol 26(3);382-9. PMID: 14529181
Doronina03a: Doronina NV, Darmaeva TD, Trotsenko YA (2003). "Methylophaga alcalica sp. nov., a novel alkaliphilic and moderately halophilic, obligately methylotrophic bacterium from an East Mongolian saline soda lake." Int J Syst Evol Microbiol 53(Pt 1);223-9. PMID: 12656177
Lehle73: Lehle L, Tanner W (1973). "The function of myo-inositol in the biosynthesis of raffinose. Purification and characterization of galactinol:sucrose 6-galactosyltransferase from Vicia faba seeds." Eur J Biochem 38(1);103-10. PMID: 4774118
Obendorf04: Obendorf, R.L., Odorcic, S., Ueda, T., Coseo, M.P., Vassalo, E. (2004). "Soybean galactinol synthase forms fagopyritol B1 but not galactopinitols: substrate feeding of isolated embryos and heterologous expression." Seed Science Research 14:321-333.
Peterbauer02: Peterbauer T, Mach L, Mucha J, Richter A (2002). "Functional expression of a cDNA encoding pea (Pisum sativum L.) raffinose synthase, partial purification of the enzyme from maturing seeds, and steady-state kinetic analysis of raffinose synthesis." Planta 215(5);839-46. PMID: 12244450
Peterbauer02a: Peterbauer T, Mucha J, Mach L, Richter A (2002). "Chain Elongation of raffinose in pea seeds. Isolation, characterization, and molecular cloning of mutifunctional enzyme catalyzing the synthesis of stachyose and verbascose." J Biol Chem 277(1);194-200. PMID: 11675396
Peterbauer03: Peterbauer, T., Karner, U., Mucha, J., Jones, D.A., Hedley, C.L., Richter, A. (2003). "Enzymatic control of the accumulation of verbascose in pea seeds." Plant, Cell and Environment, 26:1385-1391.
Peterbauer98: Peterbauer T, Richter A (1998). "Galactosylononitol and stachyose synthesis in seeds of adzuki bean. Purification and characterization of stachyose synthase." Plant Physiol 117(1);165-72. PMID: 9576785
Peterbauer99: Peterbauer T, Mucha J, Mayer U, Popp M, Glossl J, Richter A (1999). "Stachyose synthesis in seeds of adzuki bean (Vigna angularis): molecular cloning and functional expression of stachyose synthase." Plant J 20(5);509-18. PMID: 10652123
Reed86: Reed RH, Borowitzka LJ, Mackay MA, Chudek JA, Foster R, Warr SRC, Moore DJ, Stewart WDP (1986). "Organic solute accumulation in osmotically stressed cyanobacteria." FEMS Microbiology Letters 39(1-2);51-56.
Ueda05: Ueda, T., Coseo, M.P., Harrell, T.J., Obendorf, R.L. (2005). "A multifunctional galactinol synthase catalyzes the synthesis of fagopyritol A1 and fagopyritol B1 in buckwheat seed." Plant Science 168:681-690.
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