Procollagen type I carboxy-terminal peptide (PICP) is the heterotrimeric molecule which is derived from type I collagen, an important extracellular matrix (ECM) protein in our body. There are a few methods to purify the PICP, which described only about isolating the native PICP from the fibroblast culture medium, not the recombinant protein. However, these steps are time-consuming and laborious due to complicated purification procedures, resulting in low yield. Here I report a novel method to express in mammalian cells recombinant human heterotrimeric PICP. The designed recombinant PICP not only improved expression level, but also simplified purification process. In addition, I selected scFv antibodies by screening phage-display library against purified recombinant PICP, and also obtained anti-PICP polyclonal antibody by immunizing with recombinant PICP. Finally, I developed a sandwich PICP ELISA kit which can precisely determine serum level of the native PICP from the fibroblast. The expression level of PICP indicate how many type I collagen was synthesized. Therefore, quantification of the existing PICP through ELISA system can be used for diagnosis of tissue regeneration or testing cosmetics. I hope that developed sandwich ELISA kit also can be used as useful tool for determining changes of collagen type I expression level.
