A cryptide, also known as cryptein or cryptic peptide, is a bioactive peptide produced by proteolytic cleavage of a larger precursor protein, whose biological activity is distinct from that of the parent protein. Cryptides are involved in the modulation of a variety of biological processes, including neuronal signaling, angiogenesis, immune and inflammatory responses, and cell growth. These peptides have attracted some interest in pharmacological research.
Terminology The term cryptide refers to a bioactive peptide produced by proteolytic cleavage of a larger precursor protein, while crypteins are cryptic proteins generated through similar mechanisms. Cryptides are conceptually part of the broader "cryptome", a subset of the proteome composed of proteins that can yield bioactive fragments upon fragmentation. Their study en mass is known as cryptomics.
Examples Examples of cryptides include: Lactoferricin, an antimicrobial peptide released from lactoferrin by pepsin. Hemorphins, opioid peptides derived from hemoglobin. Hemopressins, cannabinoid system modulating peptides obscured in hemoglobin. Casomorphins, opioid peptides obscured in casein. Mitocryptide-1, a neutrophil-activating peptide derived from cytochrome c oxidase subunit VIII. Mitocryptide-2, another neutrophil-activating peptide, hidden in cytochrome b.
See also Zymogen Proteose Proteolysis Neuropeptide
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