Anti-human serum albumin single-chain antibody and method for connecting polypeptide drugs to carbon end thereof

The invention discloses an anti-human serum albumin single-chain antibody and a method for connecting polypeptide drugs to a carbon end of the anti-human serum albumin single-chain antibody. According to the anti-human serum albumin single-chain antibody a, a VH (Variable fragments of heavy chain) chain area of the single-chain antibody has a CDR (Complementarity-Determining Region) amino acid sequence of a complementary recognition domain, shown as C-SEQ (Sequence)-05, C-SEQ-06 and C-SEQ-07; a VL (Variable fragments of light chain) chain area of the single-chain antibody has a CDR amino acid sequence of a complementary recognition domain, shown as C-SEQ-08, C-SEQ-09 and C-SEQ-010; and the amino sequence of the single-chain antibody and the amino sequences of polypeptide drugs are connected from a nitrogen end of the single-chain antibody by a protein linking hinge shown as C-SEQ-01 or C-SEQ-03. The single-chain antibody disclosed by the invention has small molecular weight, high antibody specificity, weak immunogenicity and good water solubility, and is easily massively produced through a fermenting way. The invention also discloses a composition manufactured by using the single-chain antibody disclosed by the invention; and the composition can effectively prolong a half-life period of the polypeptide drugs.