LINEAR POLYMERIZATION OF A GASTROPOD HEMOCYANIN.

The decreased solubility of a gastropod hemocyanin in the region of the isoelectric point has been correlated with a sharp increase in light scattering produced by the protein in solution. Electron microscopic observations on negatively stained spray preparations in the isoelectric region demonstrated that the formation of linear polymers of the molecule underlies both the increase in light scattering as well as the decreased solubility of the protein. While the linear polymerization produces chains of varying length with no evidence of interaction between chains, the polymerization proceeds with a high degree of ordering of individual molecules. On either side of the isoelectric region of this hemocyanin two forms of molecules are present, rectangular and circular. The rectangular molecules polymerize in an end-to-end fashion in the isoelectric region. The rectangular molecules which participate in the polymerization appear to be divided perpendicularly to their length into three major segments.