Saccharidic fluorescent substrates, their process of preparation and their use

An enzymatic substrate of structure (I):

• [Sac]-B(I)F
• wherein:
• [Sac] is at least one saccharidic unit selected from the group consisting of monosaccharides, an oligosaccharide having 2 to 9 saccharidic units and polysaccharides having at least 10 saccharidic units;
• B is a self-cleavable spacer arm comprising at least two subunits, selected from B spacer arms according to i) or ii), wherein
• B spacer arm i) comprises:
• a monocyclic aromatic group of formula (II) and an aromatic group of formula (III);
• wherein
• Fonc is a chemical function that is reactive toward a complementary chemical function of a fluorophore group F or a group I that inhibits the fluorescence of the fluorophore group F,
• the arrow starting at the oxygen atom carried directly by the phenyl ring represents the point of attachment to a saccharidic unit of the spacer arm via a covalent bond with the carbon atom situated in anomeric position 1 of the saccharidic unit,
• the arrow starting at the oxygen atom connected to the —CH2— radical represents the point of attachment to the aromatic group of formula (III):
• wherein
• Fonc is a chemical function that is reactive toward a complementary chemical function of a group I that inhibits the fluorescence of the group F or toward a complementary chemical function of a fluorophore group F,
• the arrow represents the point of attachment to the oxygen atom of the monocyclic aromatic group of formula (II),
• X is O, NH or S;
• and
• B spacer arm ii) comprises:
• a monocyclic aromatic group of formula (IV), a group of formula (V) and a group of formula (VI):
• wherein:
• R1 is selected from the group consisting of nitro, sulfate, amine groups and an amine protected by a protective group,
• the arrow starting at the oxygen atom carried directly by the carbon atom of the phenyl ring represents the point of attachment to a saccharidic unit of the spacer arm via a covalent bond with the carbon atom in anomeric position 1 of the saccharidic unit,
• the arrow starting at the oxygen atom attached to the —CH2— radical represents the point of attachment of to a group of the formula (V):
• wherein:
• R2 is a hydrogen atom or a C1-C4 alkyl radical,
• Fonc is a chemical function that is reactive toward a complementary chemical function of a fluorophore group F or toward a complementary chemical function of a group I that inhibits the fluorescence of a fluorophore group F,
• m is an integral number ranging from 1 to 10,
• Y is O, NH or S,
• the arrows represent the point of attachment to the group of formula (III) on the one hand and to the group of formula (VI) on the other hand:
• wherein:
• W represents O, NH or S,
• the arrow represents the point of attachment of the nitrogen, sulfur or oxygen atom denoted by W via a covalent bond with a carbon atom of the group of formula (V),
• n is an integral number ranging from 1 to 10,
• Fonc is a chemical function that is reactive toward a complementary chemical function of a fluorophore group F or toward a complementary chemical function of a group I that inhibits the fluorescence of a fluorophore group F,
• F is a fluorophore group carried by the spacer arm;
• I is a group that inhibits the fluorescence of F when in structure (I) and is a side substituent of the spacer arm;
• and
• with the proviso that the fluorophore group F is not connected directly to the inhibitor group I by any covalent bond.