эктоин

Ectoine is a cyclic tetrahydropyrimidine organic osmolyte, which was discovered in the halophilic bacterium Ectothiorhodospira halochloris. It is the most abundant solute produced by aerobic heterotrophic eubacteria and has been extensively characterized as an osmoprotectant and stabilizer for cells and biomolecules.
Ectoine is considered a member of the small molecule chaperones family (SMCs). SMCs accumulate to high intracellular concentrations, preventing the misfolding/ denaturation of proteins and other labile macromolecules.  Ectoine preserves enzymes and whole cells against harmful conditions such as freezing, drying, or heating. This molecule, among other compatible solutes, possesses the ability to conserve the proteolytic activity of trypsin and chymotrypsin. It has been shown to induce heat shock proteins and downregulate proinflammatory signals in human keratinocytes. It is not toxic to the cellular environment, even at concentrations as high as 100 mM.
Ectoine strongly inhibits the Ab42 amyloid formation in vitro, reducing the toxicity to human neurblastoma cells. Ab42 was found to be the most predominant proteolytic fragment found in amyloid plaques, thus, ectoine may act as a potential inhibitor associated with neurodegenerative diseases.

Ectoine is a carboxamidine heterocycle obtained by formal condensation of (2S)-2,4-diaminobutanoic acid with acetic acid. It has a role as an osmolyte. It is a carboxamidine, a member of 1,4,5,6-tetrahydropyrimidines and a monocarboxylic acid. It is a conjugate acid of an ectoinate. It is a tautomer of an ectoine zwitterion.