Formation of the COOH-terminal amide group of thyrotropin-releasing-factor.

The precursors of peptide hormones that possess a COOH-terminal alpha-amide group contain a glycine residue following the amino acid which is amidated in the hormone. Less than Glu-His-Pro-Gly was synthesized as a putative precursor of thyroliberin. Bovine pituitary neurosecretory granules were shown to contain an amide group-forming activity associated with an Mr of about 62 000 protein(s) which converts the tetrapeptide to thyroliberin.