Stephenson A E, DeYoreo J J, Wu L, Wu K J, Hoyer J, Dove P M
Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA.
Science. 2008 Oct 31;322(5902):724-7. doi: 10.1126/science.1159417.
Studies relating the magnesium (Mg) content of calcified skeletons to temperature often report unexplained deviations from the signature expected for inorganically grown calcite. These "vital effects" are believed to have biological origins, but mechanistic bases for measured offsets remain unclear. We show that a simple hydrophilic peptide, with the same carboxyl-rich character as that of macromolecules isolated from sites of calcification, increases calcite Mg content by up to 3 mole percent. Comparisons to previous studies correlating Mg content of carbonate minerals with temperature show that the Mg enhancement due to peptides results in offsets equivalent to 7 degrees to 14 degrees C. The insights also provide a physical basis for anecdotal evidence that organic chemistry modulates the mineralization of inorganic carbonates and suggest an approach to tuning impurity levels in controlled materials synthesis.
将钙化骨骼中的镁（Mg）含量与温度相关的研究常常报告，其与无机生长方解石预期特征存在无法解释的偏差。这些“生命效应”被认为具有生物学起源，但测量偏移的机制基础仍不清楚。我们发现，一种简单的亲水性肽，其具有与从钙化部位分离出的大分子相同的富含羧基特征，可使方解石中的镁含量增加高达3摩尔百分比。与先前将碳酸盐矿物的镁含量与温度相关的研究相比表明，肽导致的镁含量增加产生的偏移相当于7摄氏度至14摄氏度。这些见解还为有机化学调节无机碳酸盐矿化的轶事证据提供了物理基础，并提出了一种在可控材料合成中调节杂质水平的方法。
