title: High-performance liquid chromatographic enantiomeric separation of an enzyme inhibitor which possesses both a chiral center and tautomeric moieties.
abstract: The enantiomeric separation using high-performance liquid chromatography (HPLC) on chiral stationary phases (CSPs) of a chiral compound which exists in solution in several tautomeric forms is described. 2,4-Dioxo-5-acetamido-6-phenylhexanoic acid is the most potent inhibitor known for peptidylamidoglycolate lyase (PGL, EC 4.3.2.5), an enzyme which plays an essential role in carboxyl-terminal amidation of many biological peptides. Synthesis of this inhibitor entails an alkaline hydrolysis step, under which condition the compound is racemized; thus, HPLC with a CSP was employed to obtain the individual enantiomers of this inhibitor. Since 2,4-dioxo-5-acetamido-6-phenylhexanoic acid exists in solution in several tautomeric forms, the strategy of first converting this compound from its multiple enol forms into a single diketo tautomer, which was then applied to various CSPs, was employed. Successful preparative scale enantiomeric separation of this compound was achieved using a Chiralpak AD CSP. Enantiomeric separation was also accomplished on a D-penicillamine column, but this CSP was found to be less satisfactory for preparative purposes.
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta 30332, USA.
authors.forename: J
authors.initials: J
authors.lastname: Feng
authors.forename: S W
authors.initials: SW
authors.lastname: May
mesh_terms: D000081:Acetamides / Q000737:chemistry / Q000302:isolation & purification*; D019760:Amidine-Lyases / Q000037:antagonists & inhibitors; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D010396:Penicillamine / Q000737:chemistry; D011773:Pyruvates / Q000737:chemistry / Q000302:isolation & purification*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D013237:Stereoisomerism; D014982:Xenopus laevis
chemical_list: C418983:5-acetamido-2,4-dioxo-6-phenylhexanoic acid; D000081:Acetamides; D004791:Enzyme Inhibitors; D011773:Pyruvates; D011994:Recombinant Proteins; D019760:Amidine-Lyases; C068521:peptidylamidoglycolate lyase; D010396:Penicillamine