Extended recombinant polypeptides and compositions comprising same

An extended recombinant polypeptide (XTEN) comprising greater than about 400 to about 3000 amino acid residues, wherein the XTEN is characterized in that

• the sum of glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P) residues constitutes more than about 80% of the total amino acid sequence of the XTEN, and
• wherein the XTEN comprises a motif selected from the group consisting of SEQ ID NO:
• 182, SEQ ID NO:
• 183, SEQ ID NO:
• 184, SEQ ID NO:
• 185, SEQ ID NO:
• 191, SEQ ID NO:
• 198, SEQ ID NO:
• 199, SEQ ID NO:
• 200, SEQ ID NO:
• 201, SEQ ID NO:
• 202, SEQ ID NO:
• 203, SEQ ID NO:
• 1715, SEQ ID NO:
• 1716, SEQ ID NO:
• 1717, SEQ ID NO:
• 1718, SEQ ID NO:
• 1719, SEQ ID NO:
• 1720, SEQ ID NO:
• 1721, and SEQ ID NO:
• 1722.