Possible Role of Red Blood Cells in Selenocysteine Metabolism

Abstract

Selenium, an essential trace element, is incorporated in the form of selenocysteine in selenoproteins. In mammals, inorganic and organic selenium compounds are the 2 sources of selenium. Generally, organic selenium compounds, such as selenocysteine and selenomethionine, are the main selenium sources. These selenoamino acids are obtained from the diet, which contains selenium-containing proteins, and absorbed by duodenum. Then, these selenoamino acids enter the blood through the duodenal capillaries. On the other hand, selenite, an inorganic selenium compound, is taken up by red blood cells (RBCs). However, the relation between organic selenium compounds and their uptake by RBCs is not yet examined. In this study, we showed that selenocysteine is taken up by RBCs. We also showed that selenide, which is produced by the reduction of selenite, binds to hemoglobin.