Correction to the Amino Acid Sequence of Porcine Motilin

Abstract

A comparison of the electrophoretic mobilities of the tryptic peptides of natural porcine motilin and a synthetic analogue with norleucine substituted for methionine revealed the absence of the acidic peptide TR3 of the natural material. Kinetic studies with leucine aminopeptidase and dansyl-Edman degradations on this peptide revealed the presence of glutamine at position 14 and not glutamic acid as previously reported. It is suggested that in the earlier preparation of natural porcine motilin deamidation of glutamine occurred.