Carbonic Anhydrase in Calcified Endoskeleton: Novel Activity in Biocalcification in Alcyonarian
Carbonic Anhydrase in Calcified Endoskeleton: Novel Activity in Biocalcification in Alcyonarian
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DOI：
10.1007/s10126-007-9030-4
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发表时间：
2007
影响因子：
3
通讯作者：
Md. Mizanur Rahman;T. Oomori;T. Uehara
中科院分区：
文献类型：
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作者：
Md. Mizanur Rahman;T. Oomori;T. Uehara
碳酸酐酶（Carbonic anhydrase，CA）是生物体化学反应中的关键酶，在包括钙质海绵在内的许多无脊椎动物中被发现与钙化有关，但到目前为止，还没有直接证据表明珊瑚中的CA活性。然而，了解CA在Alcyonarian生物钙化过程中的作用是必要的。在这里，我们描述了新的活性CA和它的关系，钙化硬组织的形成alcyonarian珊瑚，Lobophytum crassum。我们发现两个CA蛋白，这是部分纯化的电洗脱处理，可以控制碳酸钙晶体的形态，其中之一是潜在的参与生物钙化过程。以前，我们从alcyonarian总提取物中分离出CA，进一步，我们在这里报告了一个单一的蛋白质，它具有钙结合和CA活性，并负责CaCO3成核和晶体生长。这种基质蛋白抑制沉淀的CaCO3从饱和溶液中含有CaCl2和NaHCO3，表明它可以作为一个负调节剂钙化的alcyonarians的骨片。还考察了抑制剂对酶活性的影响。这些发现有力地支持了Alcyonarian中碳酸酐酶结构域参与钙化过程的观点。我们的观察强烈地表明，基质蛋白质在alcyonarian珊瑚不仅是一种结构蛋白，而且是一种催化剂。
Carbonic anhydrase (CA) is a key enzyme in the chemical reaction of living organisms and has been found to be associated with calcification in a number of invertebrates including calcareous sponges, but until now no direct evidence has been advanced to show CA activity in alcyonarian corals. However, it is essential to understand the role of CA in the process of biocalcification in alcyonarian. Here we describe the novel activity of CA and its relationship to the formation of calcified hard tissues in alcyonarian coral,Lobophytum crassum. We find that two CA proteins, which were partially purified by electro-elution treatment, can control the morphology of CaCO3crystals and one of them is potentially involved in the process of biocalcification. Previously, we isolated CA from the total extract of alcyonarian, and further, we report here a single protein, which has both calcium-binding and CA activities and is responsible for CaCO3nucleation and crystal growth. This matrix protein inhibited the precipitation of CaCO3from a saturated solution containing CaCl2and NaHCO3, indicating that it can act as a negative regulator for calcification in the sclerites of alcyonarians. The effect of an inhibitor on the enzyme activity was also examined. These findings strongly support the idea that carbonic anhydrase domain in alcyonarian is involved in the calcification process. Our observations strongly suggest that the matrix protein in alcyonarian coral is not only a structural protein but also a catalyst.