Reinhold Öhrlein

Convenient chemoenzymatic synthesis of β-purine-diphosphate sugars (GDP-fucose-analogues)

A series of peracetylated beta-sugar-1-phosphates with L-fuco configuration are efficiently prepared chemically and coupled in high yields to purine monophosphate bases via imidazolide activation. The resulting purine diphosphate sugars are deacetylated completely by a mild treatment with commercial acetylesterase (EC 3.1.1.6) to give donor-substrates for fucosyl-transferases.

ENZYMATIC FUCOSYLATION OF NON-NATURAL TRISACCHARIDES WITH CLONED FUCOSYLTRANSFERASE VI

Abstract Non-natural sialyl-lactosamine derivatives are subjected to enzymatic fucosylation with cloned fucosyltransferase VI. The enzyme tolerates a wide range of acceptors, spanning from small and bulky aliphatic as well as charged and sulfonamide replacements of the natural N-acetyl residue.

Enzymatic α(2–3)-sialylation of non-natural disaccharides with cloned sialyl-transferase

Abstract Cloned α(2–3)sialyltransferase from rat liver is used to sialylate lactosamine derivatives. The enzyme accepts a broad range of N-acetyl substituants. The residues encompass small and bulky aliphatic replacements as well as charged and sulfonamide groups.

Enzymatic galactosylation of non-natural glucosamide-acceptors

Abstract Commercial galactosyltransferase is used to galactosylate non-natural glucosamine derivatives. The enzyme tolerates various replacements of the natural N-acetyl group including charged and sulfonamide residues.

ENZYMATIC FUCOSYLATIONS WITH PURINE-DIPHOSPHATE-FUCOSES (PDP-FUCOSES)

Abstract Two cloned fucosyltransferases, Fuc-t III and Fuc-t VI, are probed on a preparative scale with non-natural donor-substrates, in which the guanosine of the natural donor guanosine-diphosphate-fucose is replaced by other purines. Surprisingly, the novel purine-diphosphate-fucoses (PDP-Fuc) are recognized by both enzymes as donor-substrates.