Indole-3-pyruvate monooxygenase (, YUC2 (gene), spi1 (gene)) is an enzyme with systematic name indole-3-pyruvate,NADPH:oxygen oxidoreductase (1-hydroxylating, decarboxylating). This enzyme catalyses the following chemical reaction
The four substrates of this enzyme are indole-3-pyruvic acid, reduced nicotinamide adenine dinucleotide phosphate (NADPH), oxygen, and a proton. Its products are indole-3-acetic acid, oxidised NADP<sup>+</sup>, water, and carbon dioxide.
The starting material is produced from the amino acid, tryptophan, by action of the enzyme L-tryptophanâÂÂpyruvate aminotransferase. The product of the reaction is the main auxin plant hormone.