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: A gene encoding a cytochrome P450 expressed specifically at initial stages in flower-bud growth and a promoter inducing expression of the gene are provided. The cytochrome P450 gene encodes the amino acid sequences encoded by the sequence having the nucleotide 1 to 1488 or the nucleotide 1 to 1617 in SEQ ID NO. 1, and the promoter consists of the base sequence within the nucleotide 1 to 1041 in SEQ ID NO. 4 that is necessary for the promoter activity.