Native Sequence

A native sequence is a peptide whose amino acid order is identical to the naturally occurring molecule in a named organism — no substitutions, no terminal caps, no truncations and no conjugates. Naming the species is indispensable: the human, rat and porcine forms of one hormone often differ at one or more positions, so a peptide may be native for one species and an analog with respect to another.

When native material is the right choice

Native peptides are the correct reference whenever the research concerns endogenous biology — characterising receptors, raising antibodies, serving as assay calibrators, or providing the baseline against which a modified compound is judged. Examples in the catalogue are oxytocin, LL-37 and glutathione, each supplied in its naturally occurring sequence.

Being native does not make a peptide sturdy. Endogenous signalling peptides are usually designed by nature to be cleared quickly, so their unaltered forms have very short half-lives — native GLP-1 survives around two minutes, compared with about a week for its engineered analog. Nor does native mean identical to the in vivo molecule: a synthetic native sequence carries none of the glycosylation or phosphorylation found in the body unless that was added on purpose. Compare recombinant and synthetic production; see reading a sequence.

Related terms

fragment · linear peptide