METHOD OF PROCESSING RACTION MIXTURES OBTAINED DURING PRODUCTION OF INSULIN PRECURSORS BY DISULFIDE BRIDGE FORMATION, BY UTILIZING WRONG RECOMBINANTS

摘要

PCT No. PCT/EP86/00008 Sec. 371 Date Sep. 2, 1986 Sec. 102(e) Date Sep. 2, 1986 PCT Filed Jan. 11, 1986 PCT Pub. No. WO86/04335 PCT Pub. Date Jul. 31, 1986.A process for the preparation of insulin precursors of the formula (I) IMAGE (I) in which R is hydrogen or the presequence Pm-Qn-, in which P is a sequence of naturally occurring amino acids with m being from 0 to 50, Q are basic natural amino acids, and n is an integer from 1 to 4, Y represents -LysB29-ZB30-, in which Z denotes Ala, Thr or Ser, and the bridge extending from A-1 to A-21 is an insulin A-chain, the bridge extending from B-1 to B-30 represents an insulin B-chain, and X is a bridge which is bonded to the insulin A-chain at the amino group of A-1 and is bonded to the insulin B-chain at the epsilon -amino group of B-29- in which case it is bonded to the free bond of ZB30OH- or at the carboxyl group of B-30, from reaction mixtures which result from folding of insulin precursors from S-sulfonates of the formula (II) IMAGE (II) in which R, X and Y have the abovementioned meanings, which comprises the false recombinants contained in the reaction mixture being precipitated by adjustment of the reaction mixture to pH 4 to 6, the precipitate being removed in customary manner and converted by sulfitolysis into the S-sulfonate of the formula (II), and the latter then being subjected to renewed folding.