Using chromatography on nanostructured carbon sorbent we had isolated an unusual nanocomplex from filling grains of wheat and maize, which consists of only phosphatidylinositol (PI) and one protein—glutamate dehydrogenase (GDh). It was very surprising that this nanocomplex shows activity of Nicotinamide adenine dinucleotide phosphate-GDh (NADP-GDh) without any treatment. Thus, the whole body of nanocomplex shows its activity without disturbing its integrity. This makes the nanocomplex very convenient for using it as a biosensor. The main feature of nanocomplex is its high sensitivity to ammonia ions. Linear response concentration for nanocomplex is from 0.5 μM to 10 μM ammonia ions. Due to these properties the nanocomplex may be very useful as nanobiosensor for ecological monitoring of pollution by sewer waters of natural reservoirs—lakes and rivers. Also this nanosensor can be applied for determination of ammonia ions, NADPH and 2-oxoglutarate in biological liquids for clinical diagnostic.