Department of Chemistry, Indian Institute of Technology Roorkee, India.
Orig Life Evol Biosph. 2012 Feb;42(1):31-45. doi: 10.1007/s11084-012-9266-5. Epub 2012 Feb 29.
Iron oxide minerals are probable constituents of the sediments present in geothermal regions of the primitive earth. They might have adsorbed different organic monomers (amino acids, nucleotides etc.) and catalyzed polymerization processes leading to the formation of the first living cell. In the present work we tested the catalytic activity of three forms of iron oxides (Goethite, Akaganeite and Hematite) in the intermolecular condensation of each of the amino acids glycine and L-alanine. The effect of zinc oxide and titanium dioxide on the oligomerization has also been studied. Oligomerization studies were performed for 35 days at three different temperatures 50, 90 and 120°C without applying drying/wetting cycling. The products formed were characterized by HPLC and ESI-MS techniques. All three forms of iron oxides catalyzed peptide bond formation (23.2% of gly2 and 10.65% of ala2). The reaction was monitored every 7 days. Formation of peptides was observed to start after 7 days at 50°C. Maximum yield of peptides was found after 35 days at 90°C. Reaction at 120°C favors formation of diketopiperazine derivatives. It is also important to note that after 35 days of reaction, goethite produced dimer and trimer with the highest yield among the oxides tested. We suggest that the activity of goethite could probably be due to its high surface area and surface acidity.
氧化铁矿物可能是原始地球地热区沉积物的组成部分。它们可能吸附了不同的有机单体（氨基酸、核苷酸等），并催化聚合反应，从而形成第一个活细胞。在本工作中，我们测试了三种氧化铁（针铁矿、纤铁矿和赤铁矿）在氨基酸甘氨酸和 L-丙氨酸的分子间缩合中的催化活性。还研究了氧化锌和二氧化钛对低聚物形成的影响。在不进行干燥/润湿循环的情况下，在 50、90 和 120°C 三个不同温度下进行了 35 天的低聚物化研究。使用 HPLC 和 ESI-MS 技术对形成的产物进行了表征。三种形式的氧化铁都催化肽键形成（甘氨酸的 23.2%和丙氨酸的 10.65%）。每隔 7 天监测一次反应。在 50°C 下 7 天后观察到肽的形成。在 90°C 下 35 天后达到最大产率。在 120°C 下的反应有利于二酮哌嗪衍生物的形成。还需要注意的是，在 35 天的反应后，针铁矿产生的二聚体和三聚体的产率在测试的氧化物中最高。我们认为针铁矿的活性可能归因于其高表面积和表面酸度。
