Factors Involved in the Formation of Amorphous and Crystalline Calcium Carbonate: A Study of an Ascidian Skeleton

摘要: The majority of invertebrate skeletal tissues are composed the most stable crystalline polymorphs CaCO3, calcite, and/or aragonite. Here we describe a composite tissue from an ascidian in which amorphous and calcium carbonate coexist well-defined domains separated by organic sheath. Each biogenic mineral phase has characteristic Mg content (5.9 1.7 mol %, respectively) concentration intramineral proteins (0.05 0.01 wt respectively). Macromolecular extracts various (ACC) skeletons typically glycoproteins, rich glutamic acid hydroxyamino acids. calcitic phases aspartate-rich. Macromolecules extracted ACC induced formation stabilized inhibited crystallization calcite vitro. yield synthetic was 15−20%. presence facilitated stabilization ACC:  protein 0.12 % the...