A photometric ninhydrin method for the measurement of proteolysis.

Photometric microdetermination of human gamma globulin. I. Development of a quantitative flocculation-ninhydrin procedure.

Autodigestion in crude extracts of soybean leaves and isolated chloroplasts as a measure of proteolytic activity.

Two methods of measuring protein breakdown resulting from self-digestion during incubation in extracts of soybean leaves were examined. The release of free alpha-amino-nitrogen was measured with ninhydrin, and the disappearance of the large subunit of ribulose bisphosphate carboxylase (RuBPcase) was followed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Rates of protein breakd...

A modified ninhydrin reagent for the photometric determination of amino acids and related compounds.

The photometric ninhydrin method described previously (1) for use in the chromatography of amino acids has been the subject of further study during the development of the Dowex 50-X4 procedure (2). The adjustment of the pH of the effluent fractions prior to analysis required by the earlier method has been largely eliminated by increasing the strength of the buffer in the reagent 5-fold. A secon...

A photometric method for the determination of proline.

The characteristic red color produced when proline interacts with ninhydrin in acidic solutions has recently been proposed for use in the quantitative assay of this imino acid (1,Z). These methods could not, however, be applied directly to the estimation of proline in biological fluids, since other amino acids interfere to some extent and must be removed either by chromatography (1) or by destr...

Photometric ninhydrin method for use in the chromatography of amino acids.

For the investigations on the chromatographic separation of amino acids outlined in the preceding communication (1)) it was necessary to have available a suitable quantitative method for the determination of the concentration of amino acids in the effluent from the column. For this purpose, the method should be sufficiently general to include the determination of most of the amino acids and pep...