軟体動物の石灰化組織の鉱物化に関する研究-XVII

Abstract

It has suggested histochemically that acid mucopolysaccharide-protein complex participates in the initiation of mineralization of some bivalve and gastropod shells at the time when there is no shell mineral4, 5). As a further study for elucidating the significance of acid polysaccharide in shell mineralization, the chemical composition and distribution of it were examined on the shell of Hyriopsis schlegeli. The periostracum and organic matrix of nacre obtained from decalcified shells were digested with “pronase” at pH 8.0 and 50°C for 6 days and subsequently with trypsin at pH 7.5 and 37°C for 5 days, respectively. Acid polysaccharide was then separated from the digested organic matrices by the cetyl pyridinium chloride treatment as shown in Fig. 1. Fraction A which contains acid polysaccharide has a large amount of protein but little amount of hexose (Table 2) and it seems to be an acid glycoprotein with sulfuric ester. The acid glycoprotein is detected in the organic matrix of the nacre (mineralized layer) but not in the periostracum (non-mineralized layer) as seen in Table 1. From the above results, it is supposed that the sulfate group of the matrix is in some way involved in the start of mineralization of molluscan shells.