How it works
The class is deliberately defined by research context, not by a common structure. Its members range from KPV, a tripeptide of roughly 342 Da, to TB-500, a 43-residue polypeptide of nearly 5,000 Da — more than a tenfold span in size — so no single scaffold or sequence motif unifies them.
Two structural features nonetheless recur across the group and are visible on the individual compound pages. The first is metal coordination: GHK-Cu is a copper(II)-coordinated tripeptide, and the way that copper is notated is handled carefully because it is the class’s clearest example of a metal complex.
The second is fragment-derived sequences: TB-500 and Thymosin α-1 are thymosin-derived, and ARA-290 carries a modified N-terminal pyroglutamate. These are compositional descriptions — what the molecules are made of and how their termini are modified — not statements about what they do.
Because the grouping is contextual, the most reliable way to understand any member is through its own characterization record: molecular formula, sequence, mass, and the certificate for a given lot. The class page is an index into those records, not a claim that the members behave alike.
Why it matters
A research classification is a navigational and comparative tool. Grouping compounds by the context in which they are studied lets a researcher move between related molecules, compare their measured properties side by side, and see structural patterns — such as metal coordination or fragment origin — that would be invisible one compound at a time.
The wide mass range within this class is itself informative for method work: a tripeptide and a 43-residue polypeptide do not behave identically under the same HPLC gradient, nor ionize identically in ESI-MS, so the class is a useful reminder that analytical methods are tuned to the molecule, not to the label.
Classifying by context also keeps the framing honest. The class name describes where these compounds appear in the literature, not an assertion that they share an effect — and each compound page states plainly that no representation is made as to any biological effect.
At Lineará
The Regenerative & Cytoprotective class page lists every characterized member and links to its compound page, where identity (ESI-MS) and purity (RP-HPLC) are reported per lot.
GHK-Cu’s copper coordination is treated as a priority detail in the site’s chemistry review, precisely because how a metal complex is written down affects how its formula and mass are checked.