Non-specific lipid transfer proteins (ns-LTPs) belong to a large family of plant proteins whose function in vivo remains unknown. On the basis of their structure, properties and functions two main classes of lipid transfer protein have been identified in plants, ns-LTP1 and ns-LTP2 respectively. The most interesting structural feature of the ns-LTP proteins is the presence of four amphipatic α-helices which form the internal hydrophobic cavity that can bind the lipid molecules.