Immunoreactivity and biologic activity of semisynthetic [LeuB-30]-insulin: potential value in the treatment of insulin antibody-mediated insulin resistance.

Insulin analogues with different amino acids, including threonine, alanine, L-leucine, D-leucine, L-leucine amide, phenylalanine, tri-alanine, or desalanine, at the B-30 position were semisynthesized from pork insulin by the new enzymatic method. The order of ability of the insulin analogues to bind to anti-insulin sera was [AlaB-30] greater than desalanine greater than [ThrB-30] greater than [Ala-Ala-AlaB-30] greater than [D-LeuB-30], [Leu-NH2B-30],[PheB-30] greater than desoctapeptide greater than or equal to [LeuB-30]. The ability of insulin analogues with different amino acids at B-30 to bind to receptors, as well as their biologic potency tested with glucose uptake in isolated rat adipocytes, was comparable among the analogues. These results suggest that [LeuB-30]-insulin demonstrated the least immunoreactivity and has full activity in receptor binding and biologic effect, and that it may be useful for treatment of anti-insulin antibody-mediated insulin resistance.