title: Rapid preparation of human insulin and insulin analogues in high yield by enzyme-assisted semi-synthesis.
abstract: Reaction conditions are described that permit the enzyme-assisted semi-synthetic replacement of residue B30 of pig insulin (or of analogue) to proceed in very high yield in 2 h or less. Immobilized trypsin may be used as catalyst, and excess amino acid ester may be recycled after a simple extraction. Alanine-B30 may be replaced by a variety of nucleophiles, including threonine O-t-butyl ether t-butyl ester, in which case the yield of crude product is about 99%. De-protection of the B30 threonyl ester analogue of insulin thus formed then affords human insulin in an overall yield of about 92%, based on pig starting material. The product has full biological potency, as determined by depression of blood glucose concentration in rats, and showed the expected behaviour on radioimmunoassay.
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D008722:Methods; D013552:Swine; D013696:Temperature; D014357:Trypsin
chemical_list: D007328:Insulin; D014357:Trypsin