STUDIES ON PROLONGED ACTING INSULIN MOLECULAR DESIGN
长效胰岛素的分子设计研究

In order to prepare soluble and prolonged-acting insulin derivatives which is mainly directed by intramolecular interactions, a principle is proposed. That is, making some additional non-covalent bonds between monomers of insulin oligomer through residue modification so as to slow down the dissociation rate of insulin hexamer injected into the body and produce the protraction from a depot-effect. On the basis of this idea and the fine structure of insulin, molecular design and computer modelling have been undertaken which provided some rational schemes for site-directed mutagenesis mainly dealing with N-and C-terminal residues of B chain. Among others, B2-Lys/Arg and B31-Lys/Arg substitutions were analysed in some detail and semisynthseized chemically as target samples. Biological tests in rabbits showed that they really both exhibited protracted glucose lowering effects. Furthermore an X-ray structure analysis of B31-Arg human insulin has also been completed at 2 A resolution and showed a pair of additional charged hydrogen bond formed by Arg-B31 and Glu-B21 of the neighbouring monomer in a dimer, that should be the structural basis of such prolonged action. This demonstrates the rationality of our idea for the molecular design.