Oxidation of reduced pyridine nucleotides in Pasteurella tularensis: I. Distribution of diaphorases and transhydrogenases

The particulate fraction from sonicates of P. tularensis contained a very active DPNH oxidase system, but was almost inactive with TPNH. The TPNH-DPN transhydrogenase of the cell was located in the soluble fraction, while most of the DPNH-3-acetylpyridine DPN transhydrogenase activity was in the particulate fraction (or acetone powder residue). Almost no TPNH-3-acetylpyridine DPN transhydrogenase activity was present. TPNH-DPN transhydrogenase activity could be determined by coupling with the particulate DPNH-3-acetylpyridine DPN transhydrogenase. About 2 3 of the DPNH diaphorase activity was found in the soluble fraction. The DPNH/TPNH diaphorase ratio was about 0.7 for whole sonicate, and about 0.5 for the soluble fraction. Very little TPNH diaphorase activity was observed in the particulate fraction, even after treatment with acetone, butanol, or deoxycholate, or after further sonic oscillation.