The organic matrix of coleoid cephalopod shells: molecular weights and isoelectric properties of the soluble matrix in relation to biomineralization processes

Abstract

Soluble matrices of coleoid cephalopod shells, namely the organic pen of Loligo sp. and mincralized calcified shells of Spirula spirula and Sepia sp., were extracted and studied by HPLC (high-performance liquid chromatography) gel filtration and isoelectrofocusing (IEF). Molecular weights of Spirula spirula and Sepia sp. extracts are not well separated, whereas Loligo sp. shows several well-defined peaks. In Loligo sp. and Sepia sp., molecular weights of > 100 kdaltons were found. Spirula spirula yielded a profile devoid of high molecular material. The main part of the extracted matrix of the organic pen of Loligo sp. is basic. In mineralized shells of both Spirula spirula and Sepia sp., the soluble organic matrices are acidic. These results support the view that the acidity of the organic matrix is related to mineralization processes.