A new compound termed humanin was recently detected by a group of scientists in Tokyo, Japan. Humanin is a 24 amino acid linear polypeptide (Met-Ala-Pro-Arg-Gly-Phe-Ser-Cys-Leu-Leu-LeuLeu-Thr-Ser-Glu-Ile-Asp-Leu-Pro-Val-Iys-Arg-Arg-Ala) that may protect neurony from the degenerative procesecs of Alzheimer's disease. The peptide contains a methionine residue in position 1 as well as a long hydrophobic series of leucines (residues 9-12), adjacent to the critical Cys. Finally, the C-terminus is characterized by a stretch of basic amino acids (Lys-Arg-Arg) in positions 21-23. The biological effect of humanin can be modified by the exchange of some amino acids. The necessary roles of CysB and Ser14 esere indicated, and the domain from Pro3 to Pro19 was responsible for the neuroprotective action of humanin, in which seven residues turned out to be essential. This neuropeptide is also a very useful drug for the six in animal models of learning and memory deficit. Synthetically prepared [G1y14]-humanin was 1000 times more potem than natural humanin in experiments on the scopolamine-induced impairment of shon-term memory in mice.

        Key words: humanin, neuropeptide, neuroprotection, Alzheimer's disease.