Vitamin K dependent carboxylation: determination of the stereochemical course using 4-fluoroglutamyl-containing substrate.
The stereochemical course of the vitamin K dependent carboxylation has been elucidated using a (4S)-4-fluoroglutamyl-containing pentapeptide as a substrate. The absolute configuration of the [13C]-4-carboxy-4-fluoroglutamate obtained when the carboxylation was carried out with 13C-labeled sodium bicarbonate, was determined after reduction of the [13C]-4-carboxy-4-fluoroglutamyl residue into 4-fluoro-5,5'-dihydroxyleucine, hydrolysis, lactonization, and peracetylation. The absolute configuration at C-4 was determined to be S by locating the 13C label in the lactone ring of the trans isomeric lactone and in the hydroxymethyl group of the cis isomer following HPLC separation of both isomers and analysis by GC/MS/MS techniques. It follows that the vitamin K dependent carboxylation occurs with inversion of configuration.
Laboratoire de Chimie Organique Biologique, URA CNRS 493, Université Pierre et Marie Curie, Paris, France.
J
J
Dubois
C
C
Dugave
C
C
Fourès
M
M
Kaminsky
J C
JC
Tabet
S
S
Bory
M
M
Gaudry
A
A
Marquet
D000595:Amino Acid Sequence; D002264:Carboxylic Acids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D005971:Glutamates / Q000737:chemistry*; D008969:Molecular Sequence Data; D013237:Stereoisomerism; D013379:Substrate Specificity; D014812:Vitamin K / Q000378:metabolism*
D002264:Carboxylic Acids; D005971:Glutamates; D014812:Vitamin K