peptide with 2 to 45 amino acids and with a C-terminal and N-terminal L-arginine residue, Y is a genetically encodable amino acid, Z is a genetically encodable amino acid,A1 to A20 or B2 to B29 is an amino-acid sequence, which is natural or has been modified by replacement of one or more amino-acid residues, of human or animal insulins, which comprises the preproinsulin being hydrolyzed by clostr