Isolation and structural characterization of insulin, glucagon and somatostatin from the turtle, Pseudemys scripta.

摘要: The chelonians occupy an important position in phylogeny representing a very early branching from the ancestral reptile stock. Hormonal polypeptides extract of pancreas red-eared turtle were purified to homogeneity by reversed phase HPLC and their primary structures determined. Turtle insulin is identical chicken insulin. glucagon differs substitution serine threonine residue at 16 mammalian additional asparagine 28. pancreatic somatostatin somatostatin-14. crocodilians are phylogenetically much closer birds than chelonians. Alligator insulin, however, contains three amino acid substitutions relative Thus, caution required when inferring phylogenetic relationships based upon comparison sequences homologous peptides.