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THE IDENTIFICATION AND ESTIMATION OF PENTOSE IN NUCLEIC ACIDS AND NUCLEOPROTEINS

1941; Elsevier BV; Volume: 139; Issue: 2 Linguagem: Inglês

10.1016/s0021-9258(18)72949-9

1083-351X

Samuel Gurin, Dorothy B. Hood,

DNA and Nucleic Acid Chemistry

We have previously reported (1) upon a study of the Dische carbazole reaction (a), and have demonstrated that the method, with certain limitations, can be used for the identification and quantitative estimation of hexose in polysaccharides and glycoproteins.As a continuation of this study we have attempted to apply the method to a study of pentoses and the nucleic acids.EXPERIMENTAL Pentoses---A number of pentoses were examined by the carbazole procedure as previously described (1).The Evelyn photoelectric filter photometer (3) was again employed, with filters transmitting maximally at 660, 540, 520, and 420 rnp.In contrast to the color characteristics of the hexoses obtained after treatment with sulfuric acid and carbazole, the pentoses gave rise to colored solutions which, when tested with our filters, absorbed more strongly at 520 rnp than at 540 mp.In Table I are listed the e. values obtained at 520 and 420 mp for a number of pentoses as well as the calculated ratios EG~O/E~~~.There was good proportionality between the absorption measured at 520 rnp and the concentration of pentose.The ratios obtained with arabinose, ribose, and lyxose are very similar, so that they cannot be distinguished qualitatively from one another by this method.Xylose, on the other hand, yielded a very different ratio and can accordingly be readily distinguished from the other pentoses.Identification of Pentose in Nucleosides, Nucleotides, and Nucleic Acids-Adenosine, guanosine, uridine, adenylic acid, and guanylic acid (Table II) yielded E 520 / ~420 ratios which agreed closely with the 775 This is an Open Access article under the CC BY license.* ~120 refers to 6,~ at 420 mp, etc.Quantitative Estimation of Pentose--For the quantitative estimation of pentose, 1 cc. of solution containing 0.05 to 0.10 mg. of pentose is sufficient.The carbazole test was carried out as previously described (1) but the EO values at 520 rnp (rather than at 540 mp) were employed for quantitative estimations, since the observed maxima were nearer 520 mp.For a comparison an appropriate series of pentose standards treated under identical conditions was employed.Satisfactory pentose (ribose) values were obtained with adenylic acid, guanylic acid, adenosine, and guanosine (Table III).Complexes of this type containing purine groups can accordingly be satisfactorily analyzed.On the