the numbers of amino acids found in the alpha-helical conformation in insulin and proinsulin were equal and in agreement with the x-ray crystallographic data for insulin when the greenfield & fasman coefficients for alpha-helix and beta-structure were employed , whereas the chen , yang & martinez coefficients yielded too few amino acids in alpha-helix in proinsulin .
C0021641
insulin
C0033362
proinsulin