MoBiTec's pPEPTIDE vector is a fusion protein cloning tool specifically developed for stable and reproducible overexpression of recombinant proteins and, in particular, polypeptides as small as five amino acids. Proteins which have proven to be toxic to E. coli are over-expressed only after induction and therefore do not interfere with cell growth. Target proteins/polypeptides are chemically released from the fusion protein and can be subsequently purified via metal affinity chromatography even under denaturing conditions. A new His-tag region guarantees optimal yields of highly purified proteins/polypeptides. The pPEPTIDE vector system is an efficient, economical alternative to chemical peptide synthesis and is suited for preparing peptides uniformly labeled with ¹³¹⁵N.