Streptavidin (SA) is a homo-tetramer that has an extraordinarily high affinity for biotin (also known as vitamin B7). It is used extensively in molecular biology and bio-nanotechnology due to the streptavidin-biotin complex's resistance to organic solvents, denaturants (e.g. guanidinium chloride), detergents (e.g. SDS, Triton), proteolytic enzymes, and extremes of temperature and pH. Under certain conditions, however, it has been shown to form higher-order oligomeric forms.

thermal unfolding | isothermal | aggregation | resolubilization | PR-P-005