Preparation of silica gel-bonded amylose through enzyme-catalyzed polymerization and chiral recognition ability of its phenylcarbamate derivative in HPLC.
Amylose was prepared by enzymatic polymerization of alpha-D-glucose 1-phosphate dipotassium catalyzed by a phosphorylase using two kinds of the primers derived from maltopentaose, and then it was chemically bonded to silica gel to be used as a chiral stationary phase (CSP) in high-performance liquid chromatography. In method I, maltopentaose was first lactonized and allowed to react with (3-aminopropyl)triethoxysilane to form an amide bond. Amylose chains with a desired chain length and a narrow molecular weight distribution were then constructed by the enzymatic polymerization. The resulting amylose bearing a trialkoxysilyl group at the terminal was allowed to react with silica gel for immobilization. In method II, maltopentaose was first oxidized to form a potassium gluconate at the reducing terminal. After the enzymatic polymerization was performed with the potassium gluconate, the amylose end was lactonized to be immobilized to 3-aminopropyl-silanized silica gel through amide bond formation. Two amylose-conjugated silica gels thus obtained were treated with a large excess of 3,5-dimethylphenyl isocyanate to convert hydroxy groups of amylose to corresponding carbamate residues. The CSP derived through method II was superior in chiral recognition to the CSP derived from method I and showed better resolving power and higher durability against solvents such as tetrahydrofuran compared with a coated-type CSP. Influences of degree of polymerization of amylose, the spacer length between amylose and silica gel, and mobile phase compositions on chiral recognition were investigated.
Enomoto
N
N
Nakano Vinegar Co., Ltd., Aichi, Japan.
Furukawa
S
S
Ogasawara
Y
Y
Akano
H
H
Kawamura
Y
Y
Yashima
E
E
Okamoto
Y
Y
D000688:Amylose / Q000737:chemistry*; D002219:Carbamates / Q000737:chemistry*; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D008969:Molecular Sequence Data; D011108:Polymers / Q000138:chemical synthesis; D058428:Silica Gel; D012822:Silicon Dioxide; D013237:Stereoisomerism
D002219:Carbamates; D011108:Polymers; D058428:Silica Gel; D012822:Silicon Dioxide; D000688:Amylose