Insulin was isolated and purified for the first time to a grade suitable for treating diabetic patients at the University of Toronto in 1921, winning the Nobel Prize in 1923 to Frederick G. Banting (1891-1941) and John J.R. McLeod (1876-1935).
Insulin is only one member of a family of peptide hormones and growth factors that comprises ten members in humans: insulin, insulin-like growth factors I and II (IGF-I and II) and seven peptides related to relaxing.
They result from successive duplications of an ancestral gene that appeared early in animal evolution. Invertebrates also have many insulin-like peptides, e.g. 37 in the worm C. elegans and seven in the fruit fly Drosophila Melanogaster.
They play an essential role in metabolism, growth, reproduction and longevity.
Canonical structures of members of the insulin family are detailed in the full article below: insulin T and R conformation as well as IFG-I and IFG-II.
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