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Ionisation behaviour of lactose and lactulose in water as studied by 13C-n.m.r. spectroscopy

✍ Scribed by Gert de Wit; Antonius P.G. Kieboom; Herman van Bekkum

Publisher
Elsevier Science
Year
1984
Tongue
English
Weight
354 KB
Volume
127
Category
Article
ISSN
0008-6215

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✦ Synopsis

From 13C-n.m.r. titration measurements on aqueous solutions of the disaccharides lactose (M) and lactulose (1.1~) at 3-Y, pK, values for a4actopyranose (134, /34actopyranose (13.8), and p-lactulopyranose (13.9) have been derived. These values are close to those for D-glucose and D-fIWtOSe, respectively, i.e., the attached D-galactosyl group has little influence on the ionisation process. The ionised species are considered to occur either as cyclic and pseudo-cyclic structures in rapid equilibrium or as non-classical anions. This picture is consistent with that for monosaccharides.

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