A process for preparing a stabilized and partially dried reaction mixture in a ready-to-use format, said mixture comprising at least one enzyme, comprising: a) bringing into contact in a single container: i) an aqueous solution of a reaction mixture comprising at least one enzyme selected from the group formed by nucleic acid amplification enzymes, restriction enzymes, enzymes intervening in nucleic acid amplification, sequencing or characterization reactions, and mixtures thereof; and all or part of the reagents necessary for said enzymatic reaction to be carried out, and ii) an aqueous solution of a stabilizing mixture comprised of: - at least one protective agent against drying which is a non-reducing carbohydrate; - at least one inhibitor of the condensation reaction between carbonyl or carboxyl groups and amine or phosphate groups; and - at least one inert polymer capable of generating a mesh structure preventing the mobility of the dried reagents selected from the group formed by polyvinylpyrrolidone, polyethyleneglycol, dextran, starch, the compound called FICOLL, glycogen, acacia gum and mixtures thereof; in order to obtain an aqueous reaction mixture in a ready-to-use format comprising said reaction mixture together with said stabilizing mixture; and b) removing part of the water contained in said aqueous reaction mixture in a ready-to-use format obtained in step a), drying said reaction at a temperature between 15°C and 60°C and at a pressure lower than atmospheric pressure to obtain said partially dried reaction mixture in a ready-to-use format which has a moisture content greater than 1 and equal to or less than 30%. a) bringing into contact in a single container: i) an aqueous solution of a reaction mixture comprising at least one enzyme selected from the group formed by nucleic acid amplification enzymes, restriction enzymes, enzymes intervening in nucleic acid amplification, sequencing or characterization reactions, and mixtures thereof; and all or part of the reagents necessary for said enzymatic reaction to be carried out, and ii) an aqueous solution of a stabilizing mixture comprised of: - at least one protective agent against drying which is a non-reducing carbohydrate; - at least one inhibitor of the condensation reaction between carbonyl or carboxyl groups and amine or phosphate groups; and - at least one inert polymer capable of generating a mesh structure preventing the mobility of the dried reagents selected from the group formed by polyvinylpyrrolidone, polyethyleneglycol, dextran, starch, the compound called FICOLL, glycogen, acacia gum and mixtures thereof; in order to obtain an aqueous reaction mixture in a ready-to-use format comprising said reaction mixture together with said stabilizing mixture; and i) an aqueous solution of a reaction mixture comprising at least one enzyme selected from the group formed by nucleic acid amplification enzymes, restriction enzymes, enzymes intervening in nucleic acid amplification, sequencing or characterization reactions, and mixtures thereof; and all or part of the reagents necessary for said enzymatic reaction to be carried out, and ii) an aqueous solution of a stabilizing mixture comprised of: - at least one protective agent against drying which is a non-reducing carbohydrate; - at least one inhibitor of the condensation reaction between carbonyl or carboxyl groups and amine or phosphate groups; and - at least one inert polymer capable of generating a mesh structure preventing the mobility of the dried reagents selected from the group formed by polyvinylpyrrolidone, polyethyleneglycol, dextran, starch, the compound called FICOLL, glycogen, acacia gum and mixtures thereof; - at least one protective agent against drying which is a non-reducing carbohydrate; - at least one inhibitor of the condensation reaction between carbonyl or carboxyl groups and amine or phosphate groups; and - at least one inert polymer capable of generating a mesh structure preventing the mobility of the dried reagents selected from the group formed by polyvinylpyrrolidone, polyethyleneglycol, dextran, starch, the compound called FICOLL, glycogen, acacia gum and mixtures thereof; b) removing part of the water contained in said aqueous reaction mixture in a ready-to-use format obtained in step a), drying said reaction at a temperature between 15°C and 60°C and at a pressure lower than atmospheric pressure to obtain said partially dried reaction mixture in a ready-to-use format which has a moisture content greater than 1 and equal to or less than 30%.