Telomerase

Telomerase is a ribonucleoprotein enzyme that adds telomeric repeat sequences (TTAGGG) to chromosome ends, counteracting the shortening that occurs during DNA replication. The catalytic subunit is TERT (telomerase reverse transcriptase) and the RNA template subunit is TERC.

Telomerase activity is high in embryonic stem cells, hematopoietic progenitors, and germline cells — and aberrantly high in most cancers — but is largely suppressed in differentiated somatic cells. This suppression is part of the body’s anti-cancer architecture: limiting replicative potential limits the number of mutations a cell can accumulate before reaching senescence.

Epitalon, a four-amino-acid peptide (Ala-Glu-Asp-Gly), is the most-cited research peptide associated with putative telomerase induction. Studies in cell culture and small-animal models report telomerase activation; the human evidence is more limited and protocol design varies widely.