The Micro Determination of Pentose in Yeast Nucleic Acid and Its Derivatives

In recent years, pentoses, in combined form, have been found to be widely distributed in the animal organism. Inosinic acid has long been known to be present in muscle (1). Guanine nucleotide, adenine nucleotide, and cytosine nucleotide have been found in the fl-nucleoprotein obtained from the pancreas (2). Adenine nucleotide, too, has been isolated from blood (3). This widespread distribution implies a definite r61e on the part of pentoses in the animal economy. A study of this rale, however, has so far not been undertaken, chiefly because no attack is possible until a reliable, accurate, and convenient method is obtained of estimating minute amounts of pentose in free or combined form. The present investigation was undertaken to devise such a method, preparatory to a study of pentose metabolism. At the same time, a method having been devised, a study has been made of the pentose partition in yeast nucleic acid. All modern methods of estimating pentose depend upon t’he conversion of pentose into furfural by distillation with 12 to 20 per cent hydrochloric acid. The furfural obtained has been determined in various ways, the most commonly used depending upon the precipitate formed by furfural with phloroglucinol in acid solution (4). Pervier and Gortner (5) in an excellent review of the literature, have shown the inaccuracy and infeasibility of all the methods proposed in the past for determining the furfural from pentose, and offer a new electrometric method, which gives, according to their figures, theoretical values for the estimation of pentoses. Their method, which depends on the oxidation of