Process for the preparation of .sup.13 C-labelled compounds

A process for preparing a .sup.13 C-labelled compound which comprises isomerizing a substrate in the presence of a first isomerase to form an isomerized substrate, reacting the isomerized substrate in the presence of lyase with an aldehyde .sup.13 C-labelled carbon source compound at a C-1 position to obtain a condensate specifically labelled with .sup.13 C, only in a carbon position C-1, and isomerizing the condensate in the presence of a second isomerase to obtain a first isomer specifically labelled with .sup.13 C, only in a carbon position C-1.

A process for preparing a .sup.13 C-labelled compound which process comprises reacting ribose 5-phosphate with .sup.13 C-labelled methanol in the presence of alcohol oxidase and of a formaldehyde-fixing enzyme system consisting of phosphoriboisomerase, hexulose phosphate synthase and phosphohexuloisomerase to obtain .sup.13 C-labelled fructose 6-phosphate specifically labelled with .sup.13 C, only in a carbon position C-1.

A process for preparing a .sup.13 C-labelled compound, which process comprises isomerizing ribose 5-phosphate in the presence of phosphoriboisomerae to form riburouse 5-phosphate, reacting the riburose 5-phosphate in the presence of hexulose phosphate synthase with .sup.13 C-labelled formaldehyde to form .sup.13 C-labelled hexulose 6-phosphate, and isomerizing .sup.13 C-labelled hexulose 6-phosphate in the presence of phosphohexuloisomerase to form .sup.13 C-labelled fructose 6-phosphate specifically labelled with .sup.13 C, only in a carbon position C-1, said .sup.13 C-labelled formaldehyde being formed by oxidizing .sup.13 C-labelled methanol in the presence of a alcohol oxidase.

A process for preparing a .sup.13 C-labelled compound, which process comprises reacting ribose 5-phosphate with .sup.13 C-labelled methanol in the presence of alcohol oxidase and of a formaldehyde-fixing enzyme system consisting of phosphoriboisomerase, hexulose phosphate synthase, phosphohexuloisomerase and phosphoglucoisomerase to obtain .sup.13 C-labelled glucose 6-phosphate specifically labelled with .sup.13 C, only in a carbon position C-1.

A process for preparing a .sup.13 C-labelled compound, which process comprises isomerizing ribose 5-phosphate in the presence of phosphoriboisomerase to form riburose 5-phosphate, reacting the riburose 5-phosphate in the presence of hexulose phosphate synthase with .sup.13 C-labelled formaldehyde to form .sup.13 C-labelled hexulose 6-phosphate, isomerizing .sup.13 C-labelled hexulose 6-phosphate in the presence of phosphohexuloisomerase to form .sup.13 C-labelled fructose 6-phosphate specifically labelled with .sup.13 C, only in a carbon position C-1, and isomerizing .sup.13 C-labelled fructose 6-phosphate in the presence of phosphoglucoisomerase to form .sup.13 C-labelled glucose 6-phosphate specifically labelled with .sup.13 C, only in a carbon position C-1, said .sup.13 C-labelled formaldehyde being formed by oxidizing .sup.13 C-labelled methanol in the presence of alcohol oxidase.