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The crystal structure and physicochemical properties of L-ascorbic acid 2-glucoside
T Mandai1, M Yoneyama, S Sakai
1Amase Institute, Hayashibara Biochemical Laboratories Inc., Okayama, Japan.
Carbohydrate Research
|August 3, 1992
Summary
Researchers crystallized a stable L-ascorbic acid glucoside, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), using cyclomaltodextrin glucanotransferase. X-ray analysis determined its molecular structure and crystal properties.
Area of Science:
- Biochemistry
- Crystallography
- Enzymology
Background:
- L-ascorbic acid (Vitamin C) is vital but unstable.
- Enzymatic modification can enhance ascorbic acid stability.
- Cyclomaltodextrin glucanotransferase (CGTase) produces stable ascorbic acid glucosides.
Purpose of the Study:
- To determine the molecular structure of the stable L-ascorbic acid glucoside produced by Bacillus stearothermophilus CGTase.
- To characterize the crystalline form of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G).
Main Methods:
- Enzymatic synthesis of L-ascorbic acid glucoside using CGTase.
- Crystallization of the synthesized compound from an aqueous solution.
- Single crystal X-ray diffraction analysis to determine molecular and crystal structure.
- 13C-NMR spectroscopy for structural confirmation.
Main Results:
- The stable L-ascorbic acid glucoside was identified as 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G).
- AA-2G crystallized in an orthorhombic system (space group P2(1)2(1)2(1)) with specific unit-cell dimensions.
- X-ray analysis confirmed the D-glucopyranose residue adopts the 4C1 conformation.
- Results were consistent with 13C-NMR spectral data.
Conclusions:
- The molecular structure of the stable ascorbic acid derivative AA-2G was elucidated through X-ray crystallography.
- The study provides detailed crystallographic data for AA-2G.
- Physicochemical properties of crystalline AA-2G were reported, contributing to its understanding and potential applications.