Abstract: A method for the separation of a target molecule from a mixture is described. The method employs oil bodies and their associated proteins as affinity matrices for the selective, non-covalent binding of desired target molecules. The oil body proteins may be genetically fused to a ligand having specificity for the desired target molecule. Native oil body proteins can also be used in conjunction with an oil body protein specific ligand such as an antibody or an oil body binding protein. The method allows the separation and recovery of the desired target molecules due to the difference in densities between oil bodies and aqueous solutions.

Abstract: The present invention relates to the use of a class of genes called oil body protein genes that have unique features. The discovery of these features allowed the invention of methods for the production of recombinant proteins wherein a protein of interest can be easily separated from other host cell components. The invention is further exemplified by methods for exploitation of the unique characteristics of the oil body proteins and oil body genes for expression of polypeptides of interest in many organisms, particularly plant seeds. Said polypeptides may include but are not limited to: seed storage proteins, enzymes, bioactive peptides, antibodies and the like. The invention can also be modified to recover recombinant polypeptides fused to oleosins from non-plant host cells. Additionally the invention provides a method of using recombinant proteins associated with seed oil bodies released during seed germination for expression of polypeptides that afford protection to seedlings from pathogens.