Biological Activity and Clearance of Gastrin Peptides in Dog and Man: Effects of Varying Chain Length of Peptide Fragments
Gastrin is known to exist in mammalian tissues and blood in multiple molecular forms. Six of these forms have been characterized chemically and shown to be three pair of single chain peptides in which the single tyrosine residue either is nonsubstituted (Gastrin I) or is sulfated (Gastrin II). The three pairs have a common C-terminal tetradecapeptide sequence and differ only in the number of amino acids comprising the N-terminal portion of the molecule. The largest form contains 34 amino acid residues and is known as big gastrin or G-34. The other forms are the heptadecapeptide or little gastrin (G-17) and the tetradecapeptide or minigastrin (G-14). Other gastrin peptides which have been identified immunochemically but not characterized by chemical analysis include an amino terminal fragment of G-17, a molecule slightly larger than G-34 known as Component I, and a molecule with an apparent molecular weight similar to albumin known as big-big gastrin. None of these forms has apparent biological activity. In addition, synthetic preparations have been prepared of nonsulfated human G-34, G-17, and G-14, as well as shorter C-terminal fragments of gastrin which are not known to occur naturally.
KeywordsAcid Secretion Gastric Acid Secretion Vary Chain Length Serum Gastrin Concentration Amino Terminal Fragment
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