Specific Determination of Proline in Biological Materials.

Abstract
A specific method for proline is reported, based on treatment of isatin-developed paper chromatograms with dilute acid. None of the 20 other amino acids of synthetic tissue culture medium M 150, including hydroxyproline, reacted by this procedure. The proline chromogen exhibits an absorption maximum at 600 m[mu]. The color is remarkably stable and can be used for the quantitative determination of proline over the range of 1 to 16 [mu]g.