Urine ninhydrin positive constituents

By means of a procedure described above, Hanson and Fittkau (HI) isolated seventeen different peptides from normal urine. One of them, not belonging to the main peptide fraction, consisted of glutamic acid, and phenylalanine with alanine as the third not definitely established component. The remaining peptides contained five to ten different amino acid residues and some unidentified ninhydrin-positive constituents. Four amino acids, i.e., glutamic acid, aspartic acid, glycine, and alanine, were found in the majority of the peptides analyzed. Twelve peptides contained lysine and eight valine. Less frequently encountered were serine, threonine, tyrosine, leucine, phenylalanine, proline, hydroxyproline, and a-aminobutyric acid (found only in two cases). The amino acid composi-... 

H3. Hamilton, P. B., The ion exchange chromatography of urine amino adds Resolution of the ninhydrin positive constituents by different chromatographic procedures. In Handbook of Biochemistry. Selected Data for Molecular Biology (H. A. Sober), pp. B43-B55. Chem. Rubber Publ. Co., Cleveland, Ohio, 1968. 

Body fluids other than urine have considerably less complex low-molecular-weight component spectrums, at least at the concentration levels that can be detected by these analyzers. For example, blood serum samples, when compared with urine, will have about one-fourth as many chromatographic peaks of UV-absorbing constituents and carbohydrates and about one-half as many ninhydrin-positive and organic acid chromatographic peaks. Cerebrospinal fluid appears to have about the same complexity in UV-absorbing and carbohydrate components as does blood serum, and perspiration falls somewhere between urine and serum. 

So far, the tentative chromatographic method has been used to make most of the identifications of the ninhydrin-positive and organic acid components, especially for urine constituents. This simply requires that the unknown peak has the same elution volume as a known reference compound. A significant effort has been made to provide more definite identifications for the components separated by the UV- and carbohydrate analyzers. To date, this has included over 70 UV-absorbing compounds and 18 carbohydrates, some of which are listed in Tables 1-3 (B2, M2). Tentative identification of many more compounds has been made in all four systems, and, hopefully, the efforts in confirmative identification will continue. 

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