O-PHOSPHORYLETHANOLAMINE AMMONIA LYASE, A NEW PYRIDOXAL PHOSPHATE-DEPENDENT ENZYME

O-phosphorylethanolamine ammonia lyase, a new enzyme present in vertebrate liver, has been shown to catalyze the catabolism of O-phosphorylethanolamine to equimolar quantities of ammonia, acetaldehyde, and inorganic phosphate. The enzyme occurs in the soluble fraction of the cell and has been partially purified from rabbit liver. Using 14C O-PE as substrate, the 14C acetaldehyde formed enzymatically was characterized as the 2,4-dinitrophenylhydrazone by infrared spectra and chromatography. Ethanolamine is not a substrate for the enzyme nor does the cobamide coenzyme affect its rate. The Km for O-phosphorylethanolamine was found to be 6.1 × 10-4M and for pyridoxal phosphate 2.7 × 10-7M. © 1969.