Kinetics and Mechanisms of Fe(III) and Cu(II) Reduction by Heme Proteins

这是一个由生命过程化学倡议支持下的特殊项目化学办公室颁发的奖项。其基本目标是了解血红素蛋白中电子传递的生物无机机制以及它们在细胞对痕量金属代谢中的作用。包括血红蛋白、肌红蛋白、细胞色素c和b5在内的几种血红素蛋白是Fe(III)和Cu(II)络合物的有效还原剂。通过外球电子转移机制，电子可以从血红素Fe(II)转移到金属络合物，距离可达20A。本研究涉及的问题有：1)哪些动力学参数对电子转移起调控作用？2)在血红素边缘的非特定外球电子传递和在电子转移之前金属络合物的特定位置结合中起作用的机制是什么？3)低分子量铁(III)、铜(II)络合物具有哪些可能具有生物化学意义的物理化学特征？

This is a project supported by an award from the Chemistry Office of Special Projects under the aegis of the Chemistry of Life Processes Initiative. The fundamental goal is to understand the bioinorganic mechanisms for electron transport in heme proteins and their role in the metabolism of trace metals by cells. Several heme proteins including hemoglobin, myoglobin, cytochrome c and b5 are effective reductants for complexes of Fe(III) and Cu(II). Electrons can be transferred from the heme Fe(II) to the metal complex over distances as great as 20 A by an outer sphere electron transfer mechanism. The questions addressed in this research are: 1) What kinetic parameters regulate and control the electron transfer? 2) What mechanisms are operating in the non-specific outer sphere electron transport at the heme edge and in site-specific binding of the metal complex prior to electron transfer? 3) What are the physical-chemical characteristics of low molecular weight complexes of Fe(III) and Cu(II) that may be of biochemical significance?