Densitygradient centrifugation with infectious ribonucleic acid of foot-and-mouth disease virus.

The sedimentation constant of an infectious component in ribonucleic acid preparations from foot-and-mouth disease virus has been determined by density-gradient centrifugation. A sedimentation constant of 37 Svedberg units (S(t)) was obtained. On the assumption that the relation between the molecular weight and the sedimentation constant found by Gierer is applicable to our system as well, a value of 3.1 x 10(6) was calculated for the molecular weight of the infectious component.