Difference of the organic component between the mineralized and the non-mineralized layers of Lingula shell

Abstract

1. 1. The organic matrix of the mineralized layer and the organic layer of Lingula unguis and Lingula shantoungensis shell were analysed. 2. 2. The chitin/protein ratio and the concentration of acidic amino acids of the mineralized layer were larger than those of the organic layer. 3. 3. Glucosamine was detected both in the mineralized layer and in the organic layer, whereas, substantial amount of galactosamine was detected only in the organic layer. 4. 4. These results suggest that acidic protein(s) and chitin play some important role in the growth of apatite crystal and may in part account for the lack of mineralization in the organic layers. 5. 5. Some differences in the organic component between Lingula unguis and Lingula shantoungensis were observed.