Peptide having an extending action for half-life of object peptide in plasma

An isolated chimeric peptide consisting of one or two added peptides and an object peptide wherein the added peptide is bonded to the N-terminus, the C-terminus or both of the object peptide, wherein if the added peptides are bound to both terminals, the two added peptides may be the same or different;

• the added peptide is (I),
• (I) a peptide represented by the formula B, A-B, B-C or A-B-C in which A, B and C each is represented by the following (1), (2) and (3);
• (1) A is a peptide selected from the group consisting of a peptide consisting of an amino acid sequence of amino acid numbers 1 to 4 in SEQ ID No:
• 34, a peptide consisting of an amino acid sequence of amino acid numbers 1 to 8 in SEQ ID No.:
• 67, and a peptide consisting of an amino acid sequence where 1 to 6 amino acid(s) in the above amino acid sequence is/are deleted, substituted, and/or added;
• (2) B is a peptide represented by the formula 1:
• (Wk-Xl-Y-Zm-Wn)-(Wo-Xp-Y-Zq-Wr)s,
• wherein in the formula 1, W is a basic amino acid selected from Arg Lys;
• X and Z are the same or different and selected from the group consisting of Ser, Pro, Leu, Phe, Ala, Thr, Gly, Val, Tyr, and His;
• Y is Glu or Asp;
• k is 1 or 2;
• l is an integer of 4≧l≧0;
• m is an integer of 2≧m≧0;
• 4≧l+m≧0;
• n is 1 or 2;
• o is an integer of 2≧o≧0;
• p is an integer of 4≧p≧0;
• q is an integer of 2≧q≧0;
• 4≧p+q≧0;
• r is 1 or 2;
• and s is 0 or 1;
• and
• (3) C is a peptide selected from the group consisting of a peptide consisting of amino acid numbers 10 to 17 in SEQ ID No:
• 34, a peptide consisting of amino acid numbers 14 to 17 in SEQ ID No:
• 67, a peptide consisting of an amino acid sequence where 1 to 6 amino acid(s)in the above amino acid sequence is/are deleted, and/or added, and/or 1 to 4 amino acid(s) in the above amino acid sequence is/are substituted, and the peptide contains 4 to 9 amino acid sequences being able to form a helix structure,
• and physiological activity of the object peptide is still retained, wherein the object peptide is a natural physiologically active peptide selected from the group consisting of an atrial natriuretic peptide, a brain natriuretic peptide, a C type natriuretic peptide, motilin, glucagon like peptide 1, parathyroid hormone, and calcitonin, or a derivative thereof, wherein the derivative has one or more amino acid(s) deleted from the amino acid sequence of a natural physiologically active peptide and has the desired physiological activity.