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Analytical ultracentrifugation

Analytical ultracentrifugation
In an analytical ultracentrifuge (commonly abbreviated as AUC), a sample’s sedimentation profile
is monitored in real time by an optical detection system. The sample is detected via ultraviolet
light absorption and/or interference optical refractive index sensitive system. The operator can
thus observe the evolution of sample concentration versus the axis of the rotation profile as a
result of the applied centrifugal field. With modern instrumentation, these observations are
electronically digitized and stored for further mathematical analysis.
The information that can be obtained from an analytical ultracentrifuge includes the gross shape
of macromolecules, conformational changes in macromolecules, and size distributions of
macromolecules. With AUC it is possible to gain information on the number and
subunit stoichiometry of non-covalent complexes and equilibrium constant constants of
macromolecules such as proteins, DNA, nanoparticles or other assemblies from different
molecule classes.
Analytical ultracentrifugation has recently seen a rise in use because of increased ease of
analysis with modern computers and the development of software, including a National Institutes
of Health supported software package, SedFit.