Eine modifizierte Orcinreaktion zur Bestimmung kleinster Mengen von Pentosen, Nucleosiden, Nucleotiden und Glucuronsäure

Abstract

Expts. using a modified Bial test for the quantitative photometric detn. of the pentoses l-+-arabinose, d.-xylose and d-ribose showed that the curve for ribose is essentially higher than that for the other 2 pentoses. The Ek values for adenosine and d-ribose are identical; however, they are considerably below those found for muscle adenylic acid and adenosintriphosphoric acid (ATP). The values for muscle adenylic acid are somewhat higher than those for ATP. Yeast adenylic acid gave essentially lower Ek values. The addition of equimolar amts. of phosphate to pentose or adenosine solns. decidedly inhibited the development of color. It is necessary, therefore, to remove organic phosphates before the detn. of free nucleotides and nucleosides in extracts of organs. By heating in a sealed tube to 104cC a decided deepening of color as well as identical extinction coefficients were obtained for the 3 pentoses. A marked deepening of color was obtained for adenine nucleotide by the same method. The curves for muscle adenylic acid and ATP coincided; yet, they were always higher than those for adenosine and ribose. The deviation according to the new method from theoretical value for pentose is not more than about 10% as against 60 or 47% by the old methods. A detn. of free and conjugated glucuronic acids is possible also by the new method. The curves of Ek values for menthol- and pregnandiol-glucuronic acid are identical according to the new method; however, they lie considerably below the curve determined for free glucuronic acid.