Abstract
A formalin treatment made nuclear polyhedra of the silkworm, Bombyx mori, hard to soluble in alkaline solution or digestive juice from the larvae. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the formalin-treated polyhedral protein revealed a pattern indicating fixation of protein. Alkaline protease present in the polyhedra was also inactivated by the formalin treatment. However, the solubility and the protease activity of polyhedra were recovered when they were kept in distilled water or 0.05M Tris-HCl buffer (pH7.6)-0.05M NaCl.
