[Role of intracellular proteinases and glycosidases in the degradation of the 'large glycoprotein' responsible for the neuraminidase and hemagglutinating activity of the Newcastle disease virus].

It was shown that the decrease in neuraminidase and hemagglutinin activities in Newcastle disease virus (NDV) infected cells, which was revealed in conditions of disturbed protein synthesis, could be significantly diminished by addition of an inhibitor or trypsin-like proteinases tosyl-lysil-chloromethyl keton. The same effect was caused by D-galactonolactone--inhibitor of some glycosidases. These data suggested that the action of intracellular proteinases and glycosidases are the cause of degradation of 'large glycoprotein', responsible for neuraminidase and hemagglutinin activities in NDV-infected cells.