EF-hands calcium binding regulates the thioredoxin reductase/thioredoxin electron transfer in human keratinocytes

摘要: Abstract Thioredoxin reductases purified from Escherichia coli human metastatic melanoma tissue and keratinocytes are subject to allosteric inhibition by calcium. 45Calcium has been used show that this enzyme contains a single binding site. Bound calcium does not exchange thioredoxin reductase upon dialysis for 48 hours or exposure 10−3M EGTA. An intelligenetics computer analysis yielded EF-hands site on E. with homology the first calmodulin. Calcium requires addition of natural electron acceptor oxidized which causes concentration dependent slow exchange. Due large conformational change caused it possible separate Calcium-free Calcium-bound FPLC chromatography. Human contain 5% in their acidic protein cytosol fraction. The influence extracellular intracellular equilibrium between bound versus free assessed. This was shown determine redox status via reduction thioredoxin. Our results provide evidence regulation conditions epidermis.