Sensors for 3-hydroxybutyrate detection

An amperometric analyte sensor system comprising:

• a 3-hydroxybutyrate sensing electrode comprising:
• a layer of an electroactive material;
• an enzyme layer comprising 3-hydroxybutyrate dehydrogenase enzyme in operable contact with the electroactive material, wherein the 3-hydroxybutyrate dehydrogenase enzyme comprises SEQ ID NO:
• 1 or SEQ ID NO:
• 2;
• a nicotinamide adenine dinucleotide in operable contact with the 3-hydroxybutyrate dehydrogenase enzyme;
• a mediator in operable contact with the nicotinamide adenine dinucleotide;
• and
• a 3-hydroxybutyrate modulating layer disposed over the enzyme layer, wherein the 3-hydroxybutyrate modulating layer comprises a composition that modulates diffusion of 3-hydroxybutyrate through the 3-hydroxybutyrate modulating layer.