. Author manuscript; available in PMC: 2010 Sep 30.

Published in final edited form as: Adv Drug Deliv Rev. 2009 Jul 20;61(11):940–952. doi: 10.1016/j.addr.2009.07.002

Table 2.

Thermally-responsive peptides

Peptide	^*Motif trend	Properties	References
Elastin-like polypeptides	[aPGbG]_n a = I , V b ≠ P n = 10 to 200	Reversible phase separation above adjustable transition temperature, which depends on concentration, length ‘n’, ‘a’ and ‘b’, ionic concentration. Accompanied by a change from a random coil to β-turn spiral conformation.	[89,90,95,98,152]
Leucine zippers	[abcdefg]_n a-g ≠ P. a = hydrophobic d = L e,g = charged n = 5,6	Forms coiled-coil α-helical structures in solution that disassociate upon heating to form random coil structures.	[89,91,93]
Silk-like peptides	[GAGAGS]_n n = 2 to 168	Irreversibly forms aggregates on exposure to high temperature. Accompanied by the formation of β-sheets.	[89,100,101]
Collagen-like peptides	[Gab]_n a = often P b = often P^OH n = 100 to 500	Irreversibly dissociate on exposure to high temperature. Form triple helices in solution but dissociate to form fibrils on heating.	[89,92,153]
FEK16 peptide	[FEFEFKFK]₂	An indirect temperature sensitive system. Ca²⁺ dependent assembly of β-sheet structures when stimulated using temperature responsive liposomes.	[102,103]

A=Alanine, E=Glutamic acid, F= Phenylalanine, G=Glycine, I=Isoleucine, K= Lysine, L=Leucine, P=Proline, P^OH=Hydroxyproline Q= Glutamine, S=Serine, V=valine.