title: A new pre-column derivatization for valienamine and beta-valienamine using o-phthalaldehyde to determine the epimeric purity by HPLC and application of this method to monitor enzymatic catalyzed synthesis of beta-valienamine.
abstract: Valienamine and β-valienamine are representative C7N aminocyclitols with significant glycosidase inhibition activity that have been developed as important precursors of drugs for diabetes and lysosomal storage diseases, respectively. The quantitative analysis of these chiral compounds is crucial for asymmetric in vitro biosynthetic processes for converting valienone into valienamine epimers using aminotransferase. Here, we developed an efficient and sensitive method for separation and quantitative analysis of chiral valienamine using reversed-phase high-performance liquid chromatography (HPLC) through o-phthalaldehyde (OPA) pre-column derivatization of the analytes. The epimers were derivatized by OPA in borate buffer (pH 9.0) at room temperature for 30 s, separated on an Eclipse XDB-C18 (5 μm, 4.6 × 150 mm) column, eluted with 22% acetonitrile at 30 °C for 18 min, and detected by a fluorescence detector using 445 nm emission and 340 nm excitation wavelengths. The average resolution of the epimers is 3.86, and the concentration linearity is in the range of 0.02-20 μg/ml. The method proved to be effective, sensitive, and reliable with good intra- and inter-day precision and accuracy, and successfully evaluated the enantiopreference and catalytic capability of the potential aminotransferases on an unnatural prochiral substrate, facilitating the design of an asymmetric biosynthetic route for optically pure valienamine and β-valienamine.
authors.affiliation: a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China.
authors.forename: Li
authors.initials: L
authors.lastname: Cui
authors.affiliation: a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Guan
authors.affiliation: a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China.
authors.forename: Zhang-Min
authors.initials: ZM
authors.lastname: Liu
authors.affiliation: a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China.
authors.forename: Liu-Yin
authors.initials: LY
authors.lastname: Fan
authors.affiliation: b School of Life Science & Technology , China Pharmaceutical University , Nanjing 210009 , China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Feng
mesh_terms: D002384:Catalysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D053138:Cyclohexenes / Q000138:chemical synthesis* / Q000737:chemistry; D006595:Hexosamines / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism; D009764:o-Phthalaldehyde / Q000737:chemistry*
chemical_list: D053138:Cyclohexenes; D006595:Hexosamines; C030791:valienamine; D009764:o-Phthalaldehyde
keywords: HPLC; Valienamine; chiral amine; derivatization; epimer separation