Determining the concentration of analytes in sample by direct mediation of enzymes
View Patent ↗The glucose content of blood can be determined by contacting a blood sample with a test strip containing a glucose dehydrogenase dependent on PQQ (or derivatives or isomers) thereof as a co-factor, a tetrazolium salt indicator, but in the absence of a mediator.
1. A reagent for measuring the concentration of glucose in blood comprising:
(a) a glucose dehydrogenase (GDH);
(b) as a co-factor for GDH, pyrrolo-quinoline quinone (PQQ) or a PQQ derivative or isomer, said GDH and co-factor being capable of reducing to a colored formazan a tetrazolium salt indicator in the absence of a separate mediator; and
(c) a tetrazolium salt indicator.
2. A reagent of claim 1 , wherein said glucose dehydrogenase of (a) is classified according to International Union of Biochemistry and Molecular Biology; Nomenclature and Classification of Enzyme-Catalyzed Reactions (i.e., NC-IUBMB) as EC1.1.99.17 (now EC1.1.5.2).
3. A reagent of claim 1 , wherein said co-factor is PQQ.
4. A reagent of claim 1 , wherein said co-factor is a PQQ derivative or isomer.
5. A reagent of claim 1 , wherein said tetrazolium salt indicator is WST-4.
6. A reagent of claim 1 , wherein said tetrazolium salt indicator is an analog of HTC-45.
7. A test strips for measuring the glucose in blood comprising:
(a) a support;
(b) a reagent layer disposed on said support, said reagent system comprising;
(1) a glucose dehydrogenase (GDH);
(2) as a co-factor for GDH, pyrrolo-quinoline quinone (PQQ) or a PQQ derivative or isomer, said GDH and co-factor being capable of reducing to a colored formazan a tetrazolium salt indicator in the absence of a separate mediator; and
(3) a tetrazolium salt indicator.
8. A test strip of claim 7 , wherein said glucose dehydrogenase of (b) (1) is classified according to NC-IUBMB as EC1.1.99.17 (now EC1.1.5.2).
9. A test strip of claim 7 , wherein said co-factor is PQQ.
10. A test strip of claim 7 , wherein said co-factor is a PQQ derivative or isomer.
11. A test strip of claim 7 , wherein said tetrazolium salt indicator is WST-4.
12. A test strip of claim 7 , wherein said tetrazolium salt indicator is an analog of HTC-45.
13. A method for measuring glucose in blood comprising:
(a) a support;
(b) a reagent system disposed on said support, said reagent system comprising a glucose dehydrogenase (GDH), as a co-factor for GDH pyrrolo-quinoline quinono (PQQ) or a (PQQ) analog, said GDH and co-factor being capable of reducing a colored formazan a tetrazolium salt indicator in the absence of a separate mediator, and a tetrazolium salt indicator;
(c) measuring the color developed from said tetrazolium salt indicator; and
(d) correlating the color developed in step (b) with the glucose content of said blood sample.
14. The method of claim 13 , wherein said glucose dehydrogenase is classified as EC1.1.99.17.
15. The method of claim 13 , wherein said co-factor is PQQ.
16. The method of claim 13 , wherein said co-factor is a PQQ derivative or isomer.
17. The method of claim 13 , wherein said tetrazolium salt indicator is WST-4.
18. The method of claim 13 , wherein said tetrazolium salt indicator is an analog of HTC-45.