| 摘要 |
Ribonuclease DNA coding for an amino acid sequence beginning with a residue of glutamine is introduced into evictor of pET22b(+) plasmid to form recombinant plasmid DNA that begins with a Pel B leader sequence. The recombinant plasmid DNA is used to transform an E.coli BL21(DE3) host. Signal peptidase enzyme present in the host cell cleaves the pelB leader sequence during signal processing and thereby allows the glutamine residue to autocyclize to pyroglutamic acid. In this way, the Ribonuclease can be produced directly, i.e. without a separate step of cleaving the initial N-terminal methionine residue.
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