Determination of binding properties of low molecular weight substances to proteins using ultracentrifugation

A method is described for the determination of the binding properties of low molecular weight (LMW) components using the analytical ultracentrifuge and a Tiselius-type partition cell. The applicability of the method is shown for two examples of protein binding: 1. 1. The interaction of manganous ion with bovine serum albumin over a wide range of manganese concentration. 2. 2. The binding of the competitive inhibitor ornithine to arginase. Binding constants as well as the number of binding sites were determined for each ligand and the values obtained compared to results by other independent methods. The applicability and accuracy of the method are discussed in comparison with other techniques and the advantages and disadvantages enumerated.