A multicatalytical protease complex from pituitary that forms enkephalin and enkephalin containing peptides

The pituitary contains a high molecular weight (M.W.～700,000) neutral endopeptidase complex that behaves in solution as a single protein, but on polyacrylamide gel electrophoresis under dissociating conditions shows the presence of five components with molecular weights of 24,000 to 28,000. The complex exhibits trypsinlike, chymotrypsinlike and peptidylglutamyl-peptide bond hydrolysing activities. Experiments indicate that each of these activities is associated with a separate component of the complex. The chymotrypsinlike and trypsinlike activities efficiently generate Leu-enkephalin, Leu-enkephalin-Arg⁶ and Leu-enkephalin-Arg⁶-Phe⁷ from a single synthetic precursor. Selective inhibition of the chymotrypsinlike activity enhances the trypsinlike activity and alters the relative proportion of opioid peptides formed.