Beckman Coulter analytical ultracentrifugation is the most versatile, rigorous and accurate means for determining the molecular weight, hydrodynamic, stoichiometry, protein aggregation, ligand binding, conjugation efficiency, polydispersity and thermodynamic properties of a protein or other macromolecule. It can be used to investigate nearly any type of molecule or particle over a wide range of concentrations and in a diverse variety of solvents. Currently, there is no other technique capable of providing the same range of information with a comparable level of precision and accuracy. In contrast to other methods used to analyze macromolecules, analytical ultracentrifugation (AUC) enables characterization of samples in their native state under biologically relevant solution conditions. AUC gives researchers two complementary views of solution behavior. Sedimentation velocity provides first-principle, hydrodynamic information about the size and shape of molecules, oligomeric state and interactions of protein and protein complex in solution. Sedimentation coefficient/equilibrium provides the same type of information about the solution molar masses, hydrodynamic, stoichiometries, association constants and solution nonideality.
 

The molecular weight of the protein can be determined from the sedimentation coefficient and the shape of the protein in solution. The hydrodynamic radius of the protein, which provides information on the protein’s shape and size in solution, can be determined from the sedimentation coefficient and the viscosity of the solution. The thermodynamic properties of the protein, such as its binding affinity or cooperativity, can be determined by analyzing the sedimentation data under different conditions, such as different protein concentrations or the presence of ligands or other molecules. The steps for AUC analysis of stoichiometry, protein aggregation, ligand binding, conjugation efficiency, and polydispersity are similar to those for molecular weight, hydrodynamic, and thermodynamic properties, but with some differences in the experimental setup and data analysis.

  Sedimentation velocity data obtained from AUC can yield important insights into the size, shape, and interactions of proteins and protein complexes in solution. The common analysis results include the sedimentation coefficient distribution used to estimate the molecular weight of the molecule; diffusion coefficient provides information on the hydrodynamic size of the molecule and can be used to estimate its shape and conformation in solution; oligomeric state of a protein complex – if the sedimentation coefficient is concentration-dependent, it indicates that the complex is dissociating into its subunit; and by analyzing the sedimentation behavior of the molecules ( protein-protein interactions and protein-ligand interactions) in the presence and absence of the interacting partner, the interaction parameters, such as the association constant and stoichiometry, can be estimated.

  AUC has several applications in the field of drug development and drug discovery, including the determination of drug binding affinity, study of drug-target interactions, characterization of drug delivery systems, study of drug formulation stability, and determination of pharmacokinetic parameters.
AUC is a powerful tool for characterizing the physical properties and behavior of peptides and polymers, which can help researchers understand their structure-function relationships such as molecular weight and size; analysis of conformational changes; interactions with other biomolecules, such as proteins or nucleic acids, or with various solvents or surfactants; self-assembly and aggregation is important for understanding their behavior in solution and their suitability for various applications such as drug delivery or nanotechnology, as well as guide the design and optimization of these biomolecules for various applications.

  AUC can be a powerful tool in the food industry, helping in the development of new food products, optimization of existing ones by characterization the physical properties and behavior of food proteins/food emulsions, including their molecular weight, size distribution, and interactions with other components in food systems, for example the development of new emulsion-based food products, such as dressings or sauces; analysis of food additives and detection of food adulteration by identifying changes in the physical properties of food components, such as protein or lipid profiles.