Crystal Structure, Solubility, and Mutarotation of the Rare Monosaccharide d-Psicose

Abstract

X-ray crystal analysis for d-psicose (C3-position epimer of d-fructose) crystallized from aqueous solution was successfully performed for the first time. It was confirmed that d-psicose crystallized solely as β-d-pyranose with 1C (1C4 (d)) conformation. The crystal system (orthorhombic), space group (#19, P212121), and number of molecules per unit cell (Z = 4) are the same as those for β-d-fructopyranose, α-l-sorbopyranose, and α-d-tagatopyranose. Solubility of d-psicose at 25 °C was 291 g per 100 g water. Mutarotation was further investigated recording the time course of specific rotation [α] at 589 nm after the dissolution of d-psicose in water. It is thought that [α] for β-d-psicopyranose in water may be ca. −85 deg dm−1 g−1 cm3. The time course of absorbance at 280 nm after the dissolution of d-psicose was also measured to see the development of open-chain carbonyl-form in the solution, and the first-order kinetic behavior with the rate constant k = 4.44 ms−1 was confirmed. Assuming the equilibrium content of carbonyl-form of d-psicose as 0.2%, the molar absorption coefficient, ε, for the carbonyl-form was estimated to be 160 cm−1 M−1.

Investigation of Selective Recognition of Sugars Using Lectin-inspired Temperature-responsive Polymers

“…24 It is known that glucose and fructose adopt a pyranose structure that cyclizes at C 6 , whereas psicose has a furanose structure cyclized at C 5 . 25 It is possible that this difference in structure accounts for the higher binding energy, as the most stable sugar structure in aqueous solution affects the strength of interaction with MAAmBO. The chirality recognition ability of the benzoxaborole group was also investigated by comparing the temperature-dependent turbidity profiles of poly(NIPAAm-st-HEAAm-st-MAAmBO) using D-glucose, L-glucose, and D-deoxyglucose ( Figure 3).…”

Recent advances on applications and biotechnological production of d-psicose

“…1), its melting temperature is 96°C, and it is highly soluble in water; at 25°C (50°C), 291 g (489 g) of D-psicose can be dissolved in 100 g water to give a 74 wt% (83 wt%) solution with density of 1.35 g cm −3 (Fukada et al 2010). The chemical and biological properties of D-psicose are shown in Table 1.…”

“…The chemical and biological properties of D-psicose are shown in Table 1. D-Psicose crystallizes solely as β-D-pyranose with 1C ( 1 C 4 (D)) conformation, even though it consists of five tautomers, α-furanose, β-furanose, α-pyranose, β-pyranose, and carbonyl form in aqueous solution (Fukada et al 2010). It has 70 % of the sweet taste of sucrose when compared in 10 % solutions (Oshima et al 2006).…”

“…It was suggested that D-psicose might be of therapeutic value in the treatment of neurodegenerative and atherosclerosis diseases. Application in food system D-Psicose was suggested as an ideal sucrose substitute for food products, due to its sweet taste (Oshima et al 2006), high solubility (Fukada et al 2010), extremely low calories (Matsuo et al 2002a), and low glycemic response (Matsuo 2006). Adding D-psicose in food products could improve the gelling behavior and produce good flavor through Maillard reaction with food proteins, such as dried egg white and ovalbumin .…”

Recent advances in d -allulose: Physiological functionalities, applications, and biological production

“…( 1 C 4 (D)) conformation (Fukada et al, 2010). D-Allulose, which contains one ketone group, acts as a reducing D-ketose.…”