Glucose dehydrogenase/cytochrome fusion protein

1. A fusion protein of pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) and a cytochrome, wherein the cytochrome has been fused to the C-terminal side of PQQGDH, and wherein the PQQGDH is either (a) or (b):

(a) a protein comprising an amino acid sequence represented by SEQ ID NO: 2;

(b) a protein comprising an amino acid sequence in which one amino acid residue has been deleted, substituted or added in the amino acid sequence (a) and having a glucose dehydrogenase activity and an electron transfer ability, and wherein the cytochrome is cytochrome c or cytochrome B562.

2. The fusion protein according to claim 1 , wherein the cytochrome is derived from a quinohemoprotein which is a protein having both PQQ and a heme in one molecule.

3. The fusion protein according claim 1 , wherein the cytochrome is derived from a quinohemoprotein alcohol dehydrogenase.

4. The fusion protein according to claim 1 , wherein the cytochrome is derived from quinohemoprotein ethanol dehydrogenase from Comamonas testosteroni .

5. An enzyme electrode comprising the fusion protein according to claim 1 attached thereto.

6. A method of measuring the glucose concentration in a sample comprising the steps of

contacting the sample with the enzyme electrode according to claim 5 ; and

measuring electrons generated from the oxidation of glucose.

7. A glucose sensor comprising an enzyme electrode according to claim 5 as a working electrode.