Association of reduced diphosphopyridine nucleotide cytochrome c reductase activity with meningopneumonitis virus.

DPNH cytochrome c reductase activity has been found associated with the MP virus isolated from the infected allantoic fluids or yolk sacs of fertile eggs and treated with trypsin, perfringens toxin, and cobra venom. The corresponding normal tissue enzymes can be nearly completely destroyed by such treatment, also the small activity found in crude preparations of influenza virus is destroyed by this treatment. Under certain relatively mild conditions of inactivation, loss in enzymatic activity is parallelled by loss in infectivity.