The Stability of Pyridine Nucleotides

Abstract

Diphosphopyridine nucleotide and triphosphopyridine nucleotide when used in appropriate enzyme systems become exceedingly useful reagents for the measurement of almost any biochemical substance. A companion paper describes procedures for measuring each of the pyridine nucleotides, whether in the oxidized or reduced form, at concentrations as low as 1O-g M and in amounts as small as lo-l5 moles (1). To exploit this sensitivity it was necessary to know more about the stability of the oxidized and reduced forms of the two nucleotides under a variety of conditions. It is well known that the reduced pyridine coenzymes may be destroyed by acid without damaging the oxidized forms (2, 3) and that, conversely, the oxidized nucleotides may be destroyed by alkali without the slightest loss of the reduced forms (3-6). This extreme difference in behavior is a key to their enormous analytical potential.