Transport of metal ions-Structural and functional analysis of a novel metal transporter

点击翻译按钮获取中文摘要

In this study, we investigated on Mg-dechelation reaction using artificial substrate, Mg-chlorophyllin, instead of true substrate, chlorophyllide a. During this study, an involvement of Mg-dechelating proteins in addition to the Mg-dechelating substance (MCS) was found. Here, we report the results of this study. The results revealed the presence of at least three isozymes which have Mg-releasing ability. We designated these proteins as Mg-releasing protein (MRP) and purification and characterization of these proteins were carried. Molecular weight of two proteins was estimated to be 20 k and 43 k. The enzyme reaction was strongly inhibited by free radical scavengers as similar to horseradish peroxidase. Absorption spectrum of MRP was, however, very different from that of horseradish peroxidase. The Mg-releasing protein had no activity for chlorophyllide a, a true substrate. It is likely to conclude that MRPs involve Mg-releasing and /or transport, but they are different from Mg-dechelatase that participates releasing of Mg in the chlorophyll degradation pathway. We are now studying on the MRP having 43 k and one another isozymes and cloning of MRP gene.