Metal Ions In Biological Systems Research Articles

Metal ions in biological systems. II. The use of p M indicators in the presence of large molecules. A determination of the association constant of serum albumin

The two wavelength p M spectrophotometric method previously introduced (1) for the determination of metal ions, and shown to be valid in the presence of small molecules, has been extended to the case of media containing macromolecules such as proteins. The interaction of calcium with bovine serum albumin, using murexide as indicator, was chosen for investigation since it permitted a comparison of the binding constant thus derived with the values found in the literature and obtained by methods based on a wider variety of principles than for any other protein.

Metal ions in biological systems. A determination of p M by spectrophotometry of metal indicators at two wavelengths

A two-wavelength spectrophotometric method has been described for the determination of metal-ion concentrations with p M indicators. A single standardization of the indicator is sufficient, using metal-ion dilutions, or metal buffers. The volume and the aging of the indicator solution are not critical as in other methods. The first characteristic may be of great value when the solvent volume is not exactly determined.