Reagent system and process for adenosine triphosphate monitoring
A reagent system comprises a first reagent which includes a high pH phosphate buffer, and a second reagent which includes luciferase, luciferin, a magnesium salt and an enzyme stabilizer. The second reagent has a low pH and a buffer with a pK which is near the optimum pH for activity of luciferase. The reagent system may be used in a process for measuring total adenosine triphosphate (ATP) and/or dissolved extracellular ATP, in a fluid containing microorganisms. The reagent system may also be used in a microbiological remediation or production process.
1. A method of estimating cellular adenosine triphosphate (ATP) based on the actual measurement of both extracellular ATP and total ATP in a sample, which comprises the step of applying a reagent system to the sample, the reagent system comprising:
a first reagent which includes a high pH having a range of about pH 9.9 to 12 phosphate buffer; and
a second reagent which includes luciferase, luciferin, a magnesium salt and an enzyme stabilizer, said second reagent having a low pH range of about 6 to 8.5 and a buffer with a pK which is near the optimum pH for activity of luciferase;
wherein the application of said first and second reagents to said sample is operable for measuring extracellular ATP in said sample, and wherein the application to said sample of said first reagent together with a cationic surfactant and said second reagent is operable for measuring total ATP in said sample.
2. The method of claim 1 , wherein said high pH phosphate buffer comprises trisodium phosphate.
3. The method of claim 1 , wherein said first reagent further comprises a cationic surfactant.
4. The method of claim 1 or 3 , wherein said first reagent further comprises a base.
5. The method of claim 1 , wherein said cationic surfactant is a quaternary ammonium salt.
6. The method of claim 5 , wherein said quaternary ammonium salt is benzalkonium chloride.
7. The method of claim 4 , wherein said base is sodium hydroxide.
8. The method of claim 1 , wherein said first reagent has a pH which is greater than about 9.9.
9. The method of claim 1 , wherein said first reagent has a pH of about 11.1 to 11.7.
10. The method of claim 1 , wherein the second reagent further comprises a chelating agent.
11. The method of claim 1 , wherein said stabilizer is selected from a combination of an enzyme hydrogen-bond stabilizer, a protein enzyme stabilizer, and a reducing agent.
12. The method of claim 11 , wherein the combination comprises trehalose, bovine serum albumin and dithiolthreitol.
13. The method of claim 10 , wherein said chelating agent is ethylenediamine tetra acetic acid (EDTA).
14. The method of claim 1 , wherein the pH of the second reagent is adjusted to pH 6 to 8.5.
15. The method of claim 1 , wherein the pK of the second reagent is about 7.5 to 8.5.
16. The method of claim 13 , wherein the pK of the second reagent is about 7.5 to 7.75.
17. The method of claim 1 , wherein the pH of the second reagent is adjusted to about pH 7.0.
18. The method of claim 1 , wherein luciferase is selected from native luciferase and recombinant luciferase.
19. The method of claim 18 , wherein said native luciferase is obtained directly from fireflies.
20. The method of claim 1 , wherein luciferase is immobilized on a support substrate.
21. The method of claim 20 , wherein said support substrate is a transparent material or a translucent material selected from the group consisting of glass and silica.
22. The method of claim 20 , wherein luciferase is re-usable.
23. The method of claim 1 , wherein said buffer of the second reagent is selected from the group consisting of N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulfonic acid] (HEPES), N-[tris(hydroxymethyl)methyl]glycine (TRICINE), N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl] glycine and combinations thereof.
24. The method of claim 1 , wherein the second reagent is reconstituted from a freeze-dried formulation.
25. The method of claim 2 , wherein the trisodium phosphate is at a concentration of about 0.5 to 500 mM.
26. The method of claim 2 , wherein the trisodium phosphate is at a concentration of about 5 mM.
27. The method of claim 10 , wherein said chelating agent is in an amount of about 0.03 to 1.3% by weight of the second reagent.
28. The method of claim 3 , wherein said cationic surfactant is at a concentration of about 100 to 10,000 mg/L.
29. The method of claim 3 , wherein said cationic surfactant is at a concentration of about 1000 to 4000 mg/L.
30. The method of claim 4 , wherein said base is at a concentration of about 100 to 10,000 mg/L.
31. The method of claim 4 , wherein said base is at a concentration of about 600 mg/L.