Process for the specific cleavage of protein sequences from proteins

In a process for selectively cleaving a fusion protein produced from a genetically engineered microorganism containing a foreign gene, the fusion protein comprising native protein and foreign protein, the cleavage selectively occurring between the native and foreign protein, and the foreign protein being terminated at its N-terminal end by Pro, the improvement comprising incorporating the tripeptide sequence Pro-Xyz-Gly between the native and the foreign protein, wherein Xyz can be any natural amino acid and its carboxy end is attached to the amino end of Gly, and reacting the fusion protein with a collagenase whereby said Xyz-Gly bond is selectively cleaved, thereby producing a foreign protein with the sequence Gly-Pro at its N-terminal end.

In a process for selectively cleaving Met from a foreign protein produced from a genetically engineered microorganism containing a foreign gene using the direct synthesis method wherein first the codon for Met is incorporated at the terminus of the foreign gene, whereby after culturing the microorganism, a foreign protein is obtained having Met attached to its N-terminal end, the improvement comprising first incorporating into the foreign gene the codons for Met-Pro attached to the N-terminal end of the subsequently produced foreign protein instead of only Met, whereby after culturing the microorganism Met-Pro is attached to the N-terminal end of the obtained foreign protein, and subsequently, selectively enzymatically cleaving Met-Pro to produce the foreign protein per se by treatment with postproline dipeptidylaminopeptidase.

In a process for selectively cleaving Met from a foreign protein produced from a genetically engineered microorganism containing a foreign gene using the direct synthesis method wherein first the codon for Met is incorporated at the terminus of the foreign gene, whereby after culturing the microorganism, a foreign protein is obtained having Met attached to its N-terminal end, and wherein the foreign protein per se contains the sequence Uvw-Pro- at its N-terminal end, the improvement comprising first incorporating into the foreign gene the codons for Met-Pro-Zxy attached to the N-terminal end of the subsequently produced foreign protein instead of only Met, whereby after culturing the microorganism, Met-Pro-Zxy is attached to the N-terminal end of the obtained foreign protein, Uvw and Zxy being any natural amino acid except Pro, and subsequently, selectively enzymatically cleaving Met-Pro from the N-terminal end by treatment with postproline dipeptidylaminopeptidase thereby producing a foreign protein having Zxy at its N-terminal end, and then selectively cleaving Zxy by treatment with leucine aminopeptidase to produce the foreign protein per se.

In a process for selectively cleaving Met from a foreign protein produced from a genetically engineered microorganism containing a foreign gene using the direct synthesis method wherein first the codon for Met is incorporated at the terminus of the foreign gene, whereby after culturing the microorganism, a foreign protein is obtained having Met attached to its N-terminal end, the improvement comprising first incorporating into the foreign gene the codons for Met-Pro attached to the N-terminal end of the subsequently produced foreign protein instead of only Met, whereby after culturing the microorganism, Met-Pro- is attached to the N-terminal end of the obtained foreign protein, and subsequently, selectively enzymatically cleaving Met from the N-terminal end by treatment with amino-acylproline aminopeptidase thereby producing a foreign protein having Pro at its N-terminal end, and then selectively cleaving Pro by treatment with proline aminopeptidase to produce the foreign protein per se.