Department of Chemistry and Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
Chemistry. 2009 Nov 16;15(45):12303-9. doi: 10.1002/chem.200901345.
This paper describes a model system for studying the autocatalytic phosphorylation of an immobilized substrate by a kinase enzyme. This work uses self-assembled monolayers (SAMs) of alkanethiolates on gold to present the peptide substrate on a planar surface. Treatment of the monolayer with Abl kinase results in phosphorylation of the substrate. The phosphorylated peptide then serves as a ligand for the SH2 adaptor domain of the kinase and thereby directs the kinase activity to nearby peptide substrates. This directed reaction is intramolecular and proceeds with a faster rate than does the initial, intermolecular reaction, making this an autocatalytic process. The kinetic non-linearity gives rise to properties that have no counterpart in the corresponding homogeneous phase reaction: in one example, the rate for phosphorylation of a mixture of two peptides is faster than the sum of the rates for phosphorylation of each peptide when presented alone. This work highlights the use of an adaptor domain in modulating the activity of a kinase enzyme for an immobilized substrate and offers a new approach for studying biochemical reactions in spatially inhomogeneous settings.
本文描述了一个用于研究固定化底物被激酶酶自动催化磷酸化的模型系统。这项工作使用金上的烷硫醇自组装单层（SAM）在平面表面上呈现肽底物。用 Abl 激酶处理单层会导致底物磷酸化。然后，磷酸化的肽作为激酶的 SH2 衔接子结构域的配体，从而将激酶活性引导至附近的肽底物。这种定向反应是分子内的，并且比初始的分子间反应更快，因此这是一个自动催化过程。动力学非线性导致了在相应的均相反应中没有对应的性质：在一个例子中，两种肽混合物的磷酸化速率比每种肽单独呈现时的磷酸化速率之和更快。这项工作强调了在固定化底物的激酶酶中使用衔接子结构域来调节其活性，并为在空间不均匀的环境中研究生化反应提供了一种新方法。
