Molecular and ultrastructural characterization of the egg capsule of the leech Erpobdella octoculata L.

Abstract

1. 1. The high content of proline and of bulky amino acid residues and the amorphous X-ray diffraction pattern suggest that much of the protein of the egg capsule of Erpobdella octoculata is amorphous. 2. 2. The sharp thermal transition, the presence of banded fibrils apparently composed of 15 Å filaments and the amino acid composition of the trichloracetic acid extract may indicate that a small part of the protein is in the form of fibrous molecules, possibly of an α fibrous protein. 3. 3. The insolubility of the material and the presence of DOPA and orthodiphenol oxidase activity suggest stabilization by phenolic cross-linking.