| abstract |
A compound of the formula:n n wherein each of R¹ and R² is hydrogen or an aliphatic acyl group, each of R³ and R⁴ is hydrogen or a protecting group, X is an amino acid sequence consisting of 1 to 10 amino acid residues which may be protected, Y is an amino acid sequence consisting of 1 to 5 amino acids residues which may be protected, bounding at a terminal carboxyl group, or a salt thereof has an activity of remarkably improving hematopoietic disorder and is useful as an immuno-stimulating agent or an agent for treating thrombocytopenia. |