Abstract: The invention provides an isolated thermostable polypeptide possessing FGF2 activity and having at least 85% sequence identity to SEQ ID NO: 2 (FGF2 wt) or a functional fragment thereof, and comprising at least one amino acid substitution R31L and the use thereof in the cell biology research, regenerative medicine and related medical applications or cosmetics. Further it discloses a culture medium comprising subjected FGF2 suitable for culturing a human pluripotent stem cells involving both human embryonic stem cells and induced pluripotent stem cells.

Abstract: The invention provides an isolated thermostable polypeptide possessing FGF2 activity and having at least 85% sequence identity to SEQ ID NO: 2 (FGF2 wt) or a functional fragment thereof, and comprising at least one amino acid substitution R31L and the use thereof in the cell biology research, regenerative medicine and related medical applications or cosmetics. Further it discloses a culture medium comprising subjected FGF2 suitable for culturing a human pluripotent stem cells involving both human embryonic stem cells and induced pluripotent stem cells.

Abstract: Thermostabilization of a protein where the protein contains access routes and wherein at least one amino acid in the bottleneck of the access route is mutated, includes identifying the amino acids of the bottleneck and the amino acids control exchange of the solvent between a buried protein core and surrounding environment and/or in the packing of the amino acids inside the access route. Modification of the amino acids are determined so that the packing of the amino acids inside the tunnel is improved and the access route prevents access of undesired solvent molecules to the protein core, while allowing passage of the compounds necessary at the protein core to enable the protein to perform its biological function.

Abstract: Thermostabilization of a protein where the protein contains access routes and wherein at least one amino acid in the bottleneck of the access route is mutated, includes identifying the amino acids of the bottleneck and the amino acids control exchange of the solvent between a buried protein core and surrounding environment and/or in the packing of the amino acids inside the access route. Modification of the amino acids are determined so that the packing of the amino acids inside the tunnel is improved and the access route prevents access of undesired solvent molecules to the protein core, while allowing passage of the compounds necessary at the protein core to enable the protein to perform its biological function.