Human serum albumin mutant

A human serum albumin mutant-linked protein (A), the human serum albumin mutant linked protein (A) comprising a first polypeptide chain and a second polypeptide chain,

• wherein the first polypeptide chain comprises an amino acid sequence of the human serum albumin mutant, the human serum albumin mutant;
• (i) comprising an amino acid sequence, in comparison with the amino acid sequence set forth as SEQ ID NO:3, has not more than 10 amino acid residues deleted and/or has not more than 10 amino acid residues replaced, with the proviso that the asparagine residue occurring at position 318 and the threonine at position 320 numbered from the N-terminus of the amino acid sequence set forth as SEQ ID NO:3 are preserved and linked by peptide bonds via a single amino acid residue (X) except proline that is placed between those two amino acid residues, or
• (ii) consisting of the amino acid sequence set forth as SEQ ID NO:3, and
• the second polypeptide chain linked thereto comprises an amino acid sequence of the protein (A), the protein (A) being different from a human serum albumin that is a mutant or not,
• wherein a C-terminus of the second polypeptide chain is linked to a N-terminus of the first polypeptide chain by one or more peptide bonds.