PG-005 and PG-006 are special peptides that are fully chemically synthesized and possess selective inhibitory activity against the BMP7 family and BMP4 family, respectively. They make it possible to separately inhibit the BMP4/7 families, which was impossible with existing small kinase inhibitors or Noggin, and can be utilized for detailed analysis and control of BMP signaling, as well as for constructing new cellular differentiation pathways.