ENZYMATIC REPLACEMENT OF THE B-30 AMINO ACID IN INSULINS

摘要

The B-30 amino acid in insulins is replaced enzymatically by reacting as substrate component the selected insulin Ins-X, wherein X represents the B-30 amino acid with an amine component selected from the group consisting of (a) amino acids of the formula H-B-OH wherein B is an amino acid residue, (b) optionally N-substituted amino acid amides of the formula H-B-NR1R2 wherein B is an amino acid residue and R1 and R2 are independently selected from the group consisting of hydrogen, amino, hydroxy, alkyl, cycloalkyl aryl, heteroaryl and aralkyl or R1 and R2 together with the nitrogen atom form a heterocyclic group which may contain a further hetero atom, and (c) amino acid esters of the formula H-B-OR3, H-B-SR3 or H-B-SeR3 wherein B is an amino residue and R3 represents alkyl, cycloakyl, aryl, heteroaryl or aralkyl in the presence of an L-specific serine or thiol carboxypeptidase enzyme, preferably carboxypeptidase-Y, in an aqueous solution or dispersion having a pH from about 7 to 10.5, thereby to form an insulin dirivative Ins-B-OH, Ins-B-NR1R2, Ins-B-B-NR1R2, Ins-B-OR3, Ins-B-SR3 or Ins-B-SeR3 and subsequently cleaving a group -NR1R2, -B-NR1R2, -OR3, -SR3 or SeR3, if desired, preferably by using a carboxypeptidase enzyme. The cleaving may also be performed on derivatives obtained by other methods. By using porcine insulin as substrate component and threonine as the amino acid forming part of the amine component human insulin is obtained.