Nagasawa Hiromichi
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo, 113-8657, Japan,
Prog Mol Subcell Biol. 2011;52:315-29. doi: 10.1007/978-3-642-21230-7_11.
Crustaceans have hard cuticle with layered structure, which is composed mainly of chitin, proteins, and calcium carbonate. Crustaceans grow by shedding the old cuticle and replacing it with a new one. Decalcification in the cuticle during the pre-molt stage and concomitant calcification in the stomach to form gastroliths observed in some crustacean species are triggered by the molting hormone. Various proteins and peptides have been identified from calcified cuticle and gastroliths, and their functions have been examined in terms of calcification and interaction with chitin. Acidic nature of matrix proteins is important for recruitment of calcium ions and interaction with calcium carbonate. Examination of the relationship between amino acid sequence containing acidic amino acid residues and calcification inhibitory activity revealed that the potency did not depend on the sequence but on the number of acidic amino acid residues. Calcium carbonate in the calcified tissues of crustaceans is amorphous in many cases. Crustaceans take a strategy to induce and maintain amorphous calcium carbonate by using low-molecular-weight phosphorus compounds.
甲壳类动物具有分层结构的坚硬角质层，其主要由几丁质、蛋白质和碳酸钙组成。甲壳类动物通过蜕去旧的角质层并换上新的角质层来生长。在一些甲壳类物种中观察到，蜕皮前阶段角质层中的脱钙以及胃中形成胃石的伴随钙化是由蜕皮激素触发的。已经从钙化角质层和胃石中鉴定出各种蛋白质和肽，并从钙化以及与几丁质的相互作用方面对它们的功能进行了研究。基质蛋白的酸性性质对于钙离子的募集以及与碳酸钙的相互作用很重要。对含有酸性氨基酸残基的氨基酸序列与钙化抑制活性之间关系的研究表明，效力并不取决于序列，而是取决于酸性氨基酸残基的数量。在许多情况下，甲壳类动物钙化组织中的碳酸钙是无定形的。甲壳类动物采取一种策略，即通过使用低分子量的磷化合物来诱导和维持无定形碳酸钙。
