Raffinose hydrolysis

Melibiose (6-0-(3-D-Gal-D-G1c) (disaccharide) Widespread in plant exudates from Raffinose hydrolysis Sweet [[Pg.404]

Using chromatographic and heat inactivation procedures, Pazur succeeded in separating transfructosidase from Aspergillus oryzae cultures, containing a mixture of transglucosidase, invertase, and maltase. In tracer experiments the C -fructosyl units in radioactive sucrose were transferred to nonradioactive raffinose. Hydrolysis of the radioactive fructosylraffinose into fructose and melibiose, followed by a determination... 

Hydrolysis Rates of Sucrose, Raffinose and Stachyose by Purified Yeast ft-Frudofuranosidase... 

However, GrootWassink and Fleming64 reported a higher rate of hydrolysis of stachyose than raffinose for a commercial preparation of /3-D-fructofuranosidase of Saccharomyces cerevisiae. 

Hydrolysis and Utilization of Raffinose by Cultures of Saccharomyces uvarum of Various Genotypes198... 

Very successful experiments were carried out on the oxidation of sucrose, one mole of which needs three moles of periodic acid, with the formation of one mole each of formic acid and a tetraaldehyde. The latter is oxidized by bromine to a tetracarboxylic acid subsequent acid hydrolysis of the oxygen bridges affords a mixture of acids, all of which were isolated and identified. These results brought in 1943 a confirmation of the structure of sucrose which was discussed, and which gained the approval of C. S. Hudson who, before that, was a little doubtful about the furanoid form of the D-fructosyl group. Similar work was done later with trehalose. In the same way, J. . Courtois obtained confirmation of the structure of raffinose, and established that of stachyose. 

Melibiose [0-a-D-galactopyranosyl-(l—>6)-D-glucopyranose] is a constituent of the trisaccharide raffinose (see Section II,2,f), and is liberated on hydrolysis of the latter by invertase. A detailed, structural elucidation of this disaccharide was described by French.115 Melibiose is found in the exudates115 and nectaries204 of several plants, and is also found in the tissues of various plants.75,110,123 205-209 In Aconitum... 

The hydrolysis of members of the raffinose family of oligosaccharides by a-D-galactosidase yields D-galactose and sucrose. The equilibrium of this reaction favors hydrolysis therefore, the synthesis of these oligosaccharides through the back-reaction seems unfeasible. 

Emulsin hydrolysis of raffinose to sucrose and D-galactose Neuberg 1907 16... 

A comparative study of the action of yeast invertase on sucrose, raffinose, and stachyose was reported by Adams, Richtmyer and Hudson (see Table V).23 Hydrolysis by invertase has been found to give D-fruc-tose, in each case, and the complementary aldose D-glucose, melibiose, or manninotriose. In general, the same products are formed as in mild acid hydrolysis. 

Comparative Studies of the Enzymic Hydrolysis of Sucrose, Raffinose, and Stachyose,... 

Raffinose crystallizes from water, or from aqueous alcohols or acetic acid, as the pentahydrate, of m.p. 78°, [a]20D + 105.2° (c 4, in water). No crystalline, characterizing derivatives of raffinose are known. Raffinose may be exactly identified by comparison of its x-ray diffraction powder pattern with that of an authentic standard.28 Other information of value in the identification of raffinose is its extreme ease of acid hydrolysis... 

The exact structure of raffinose follows most simply from the fact that it is cleaved by mild acid hydrolysis, or by invertase action, to give D-fructose and melibiose,7 and by almond-emulsin a-D-galactopyrano-sidase to give D-galactose and sucrose.16... 

In a critical study of the periodate oxidation of raffinose and related oligosaccharides, Courtois and Wickstrom showed78 that 1 mole of raffinose reduces 5 moles of periodate, with the formation of 2 moles of formic acid plus a hexaldehyde. Conversion of the aldehyde to the hexa-carboxylic acid, followed by hydrolysis, gave the expected amounts of glyoxylic acid, glyceric acid, hydroxypyruvic acid, and glycolaldehyde (by decarboxylation of hydroxypyruvic acid). 

Wada and Yamazaki have reported42 the occurrence in tobacco seeds of a non-reducing trisaccharide isomeric with raffinose, which has now been shown to be identical with planteose.80 French and Wild noted67 the presence of planteose (detected as planteobiose, after mild, acid hydrolysis) in extracts from Teucrium canadense and in ash manna. Since planteose and planteobiose have only recently been recognized as distinct entities, it is likely that planteose may have escaped detection in many other plant sources, where it undoubtedly accompanies raffinose and stachyose. 

A more concrete demonstration28 of the presence of the sucrose linkage in stachyose was afforded by French and associates, who were able to isolate and identify sucrose and raffinose following the partial hydrolysis of stachyose by almond-emulsin a-D-galactopyranosidase. 

If the assumption that the sucrose and raffinose formed are not artifacts but are genuine hydrolysis products of stachyose is permitted, this work provides strong confirmation for the presence of sucrose (and raffinose) units in stachyose. Very recently, Courtois and associates91 have identified crystalline raffinose and sucrose, obtained from stachyose by action of coffee a-D-galactopyranosidase. 

De Whalley and his coworkers have made extensive studies on the application of paper chromatography to raffinose. To separate raffinose from large proportions of sucrose, a 1-butanol-benzene-pyridine-water solvent was used.140 81 To avoid pyridine, a 1-propanol-ethyl acetate-water mixture was recommended.141 As a color reagent, a-naph-thol-phosphoric acid was used. In this manner, less than 1 % of raffinose in cane sugar could be separated and determined. Partial hydrolysis of the raffinose, using invertase directly on the filter paper, proved useful in some instances.93 142 Melibiose was then detected with 3,5-dinitrosali-cylate142 or with diethyl-p-phenylenediamine sulfite.93... 

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