Main Reaction: choline + phosphoric acid >> 2 H2O2 + DAOS + 4-aminoantipyrine + peroxidase

Reference: PubMed ID: 18619432
Authors: Hidaka H, Yamauchi K, Ohta H, Akamatsu T, Honda T, Katsuyama T
Title: Specific, rapid, and sensitive enzymatic measurement of sphingomyelin, phosphatidylcholine and lysophosphatidylcholine in serum and lipid extracts.
Published: 2008 Oct

choline + phosphoric acid --> 2 H2O2 + DAOS + 4-aminoantipyrine + peroxidase