Abstract: The present invention relates to a method, and a kit, for measuring the enzymatic activity of cytochrome P450 comprehensively and with high efficiency and accuracy, wherein an oxygen sensing layer and a cytochrome P450-supporting layer are vertically integrated on a chip, and cytochrome P450 is supported in a hydrophilic polymer matrix in the cytochrome P450-supporting layer, the cytochrome P450 generates NADPH by being irradiated with light in the presence of at least one caged compound selected from the group consisting of caged-NADP and caged-G6P, an enzyme utilizing NADPH as a coenzyme (i.e., cytochrome P450 reductase) and a substrate thereof to supply NADP and/or G6P from the caged compound to generate NADPH to start the reaction between the enzyme and a substrate.

Abstract: An object of the present invention is to provide an electrode and a field effect transistor having excellent ion selectivity using a noncyclic peptide. In order to achieve the above object, the ion sensor of the present invention using a noncyclic peptide is an ion sensor where a noncyclic peptide is contained in a sensing membrane. The said noncyclic peptide may contain at least two kinds of natural amino acids or non-natural amino acids. The ion sensor of the present invention may be constituted by an ion-selective electrode or by an ion-selective field effect transistor. Examples of the main responding ion are magnesium ion, lead ion, potassium ion, calcium ion, nickel ion, copper ion, zinc ion and cadmium ion.