Despite the fact that PEG10 was shown to be involved in placenta, adipose tissue, and cancer formation, it is little known about this protein at a molecular level. Especially, no solid data has been published regarding a retroviral-type aspartic protease of PEG10 so far. Autoproteolytic assay performed in this project implies that PEG10 aspartyl protease is active. Analysis of protease activity became possible due to the expression of the protein in the bacterial system we designed. Preliminary results show that PEG10 may cleave itself at some sites with the formation of cleavage products having different size. The structure and the role of these products are still unrevealed. In addition, the sensitivity of PEG10 aspartic protease to retroviral protease inhibitor makes the design of new inhibitors against PEG10 a striking prospect. Therefore, future research may be aimed to elucidate the role of cleavage products in the PEG10 function with further biochemical characterization of PEG10 activity. Results presented in this work will facilitate the characterization of PEG10 aspartic protease and the role of PEG10 in human biology.