Method of improving blood kinetics of peptide

A conjugate of a peptide comprising, from the amino terminus to the carboxyl terminus, two or three aspartic acids and/or glutamic acids, the amino acid sequence of a SPINK2 variant peptide set forth in SEQ ID NO:

• 2, and an amino acid sequence comprising an Fc region of human IgG1, IgG2, or IgG4P, in this order, wherein the Fc region is represented by any one of the amino acid sequences set forth in SEQ ID NO:
• 34, 37, or 40, and
• wherein the conjugate has a suppressed blood concentration decrease over time or an increased blood exposure amount compared to a conjugate lacking the two or three aspartic acids and/or glutamic acids at the amino terminus.