In vitro characterization of antithrombin III concentrates--a single-blind study.

Twenty-three lots of five antithrombin III (AT III) concentrates from four manufacturers were analyzed in a single-blind study. All the preparations had been virus-inactivated by pasteurization, and one concentrate had also been treated with solvent/detergent (S/D). AT III activities were determined using two thrombin-based and one factor Xa-based chromogenic substrate assays.

High-performance liquid chromatography and diode-array detection for the identification of peptides containing aromatic amino acids in studies of endorphin-degrading activity in human cerebrospinal fluid.

Diode-array UV detection has been adapted for analysis of opioid peptides and their metabolic fragments differing in aromatic amino acid content. In combination with high-performance liquid chromatography, the technique allowed a direct and rapid discrimination between peptides containing phenylalanine, tryptophan and tyrosine, or a combination of these residues. Enkephalin fragments with either tyrosine or phenylalanine, or both, were identified after digestion of the pentapeptide with proteolytic activity recovered from human cerebrospinal fluid.

Ion-exchange high-performance liquid-chromatography steps in peptide purifications.

Ion-exchange high-performance liquid chromatography (HPLC; on Ultropac TSK DEAE and CM) is compared with conventional soft-gel ion-exchange chromatography in identical peptide purifications. The results show that separating properties are similar, but as expected, ion-exchange HPLC has a much higher resolving capacity and a higher sensitivity, and allows a considerably shorter total separation time. The same buffer systems as for conventional ion-exchange chromatography can be used, including urea to solubilize large peptides, if care is taken not to exceed the pH limits set by the column matrix.