THE 108-KDA PEPTIDYLGLYCINE ALPHA-AMIDATING MONOOXYGENASE PRECURSOR CONTAINS 2 SEPARABLE ENZYMATIC-ACTIVITIES INVOLVED IN PEPTIDE AMIDATION

A 43-kDa protein factor that increases the ability of purified bovine peptidylglycine α-amidating monooxygenase (PAM)-A and -B produce α-amidated peptides at physiological pH was purified to homogeneity from bovine neurointermediate pituitary. At each step of the purification, the amount of activity correlated with the amount of protein detected on Western blots by antibody to bovine PAM(561-579). In the bovine neurointermediate pituitary the 108-kDa PAM precursor protein is cleaved to form a peptidylglycine α-hydroxylating monooxygenase and a peptidyl-α-hydroxyglycine α-amidating lyase, which function sequentially in the 2-step formation of α-amidated peptides. © 1990.