Factors Influencing the Production of Intermediate Particles During Alkaline Degradation of Tobacco Mosaic Virus: Time, pH, Salt Concentration, and Temperature.

Kinetic analysis of the alkaline degradation of tobacco mosaic virus revealed degradation to be a stepwise process during which five distinct intermediate nucleoprotein particles were formed. Each intermediate accumulated before being degraded to the next smaller particle. After prolonged exposure to alkali, a stable nucleoprotein particle accumulated. The rate of alkaline degradation of tobacco mosaic virus was retarded by lowering pH (10.3 to 9.0), increasing salt concentration (0 to 100 mM), or increasing incubation temperature over the range of 0 to 22 degrees C. A fraction (15 to 25%) of the total virus population appeared to be completely resistant to alkaline degradation; however, the progeny of this virus fraction was sensitive to alkaline degradation.