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Semisynthesis and properties of some insulin analogs
Author(s) -
Inouye Ken,
Watanabe Kunio,
Tochino Yoshihiro,
Kobayashi Masashi,
Shigeta Yukio
Publication year - 1981
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1981.360200909
Subject(s) - insulin , chemistry , trypsin , human insulin , semisynthesis , insulin receptor , peptide , biological activity , biochemistry , stereochemistry , in vitro , enzyme , biology , endocrinology , insulin resistance
The trypsin‐catalyzed coupling of bovine (Boc) 2 ‐desoctapeptide (B23‐B30)‐insulin with synthetic octapeptides, H‐Gly‐ X 2 ‐ X 3 ‐ X 4 ‐Thr‐Pro‐Lys(Boc)‐Thr‐OH ( X 2 = Phe or Ala, X 3 = Phe or Ala, X 4 = Tyr or Ala), followed by deprotection and purification produced the [Ala B24 , Thr B30 ]‐, [Ala B25 , Thr B30 ]‐, and [Ala B26 , Thr B30 ]‐analogs of bovine insulin in yields of 32, 35, and 32%, respectively. The biological activity of these analogs decreased in the order, normal insulin ([Thr B30 ]‐bovine insulin) = Ala B26 ‐insulin > Ala B25 ‐insulin > Ala B24 ‐insulin, as assayed for receptor binding and some other biological effects, in contrast with the corresponding Leu‐analogs of human insulin, in which the activity decreased in the order, normal insulin > Leu B24 ‐insulin > Leu B25 ‐insulin. The affinity to insulin antibodies greatly diminished in both Ala B24 ‐insulin and Leu B24 ‐insulin but not in the B25‐substituted analogs. The CD spectra of the Leu‐ and the Ala‐analogs were compared with those of normal insulins to show that no apparent correlation seems to exist between the decrease in biological activity and the conformational changes observed in solution. The effects of organic solvents on the peptide‐bond equilibrium and on the stability of trypsin are also discussed.