ИСТИНА

The invention relates to the field of biochemistry. A reagent for the quantitative determination of adenosine-5'-triphosphate (ATP) by a bioluminescence method contains luciferase extracted from recombinant E.coli cells containing the plasmid pETL7 with a mutant Luciola mingrelica firefly luciferase gene which codes (by comparison with the initial enzyme, SEQ1) for an amino acid sequence of the enzyme with eight substitutions (Ser118Cys, Cys146Ser, Lys156Arg, Arg211Leu, Tre213Ser, Ala217Val, Glu356Lys, Ser364Cys) with the additional sequence Met-Ala-Ser-Lys at the N-end and the additional sequence Ser-Glu-Pro-Val-Glu-Gis-Gis-Gis-Gis-Gis-Gis at the C-end in place of the sequence Ala-Lys-Met (SEQ 2), luciferin, magnesium sulphate, a buffer mixture of tris-(oxymethyl)-aminomethane and acetic acid, a mixture of sodium ethylenediaminetetraacetate, dithiothreitol, bovine serum albumin and sucrose as stabilizers, and water. The reagent provides for greater sensitivity when determining adenosine-5'-triphosphate as a result of an increase in the specific activity and thermostability of the mutant luciferase. The production cost of the reagent is reduced through the use of the more readily available stabilizer sucrose in place of trehalose and also through an increase in the efficiency of the reagent production process achieved by increasing the yield of active enzyme during cultivation of the biomass, increasing the concentration of luciferase in the resultant enzyme preparation and reducing the labour intensiveness and length of the enzyme purification process.