TY - JOUR
T1 - Abundance and tissue distribution of selenocysteine-containing proteins in the rat
AU - Hawkes, Wayne C.
AU - Wilhelmsen, Eric C.
AU - Tappel, Al L.
PY - 1985
Y1 - 1985
N2 - The form and distribution of selenium (Se) in proteins from selected tissues of the rat were studied by measuring 75Se radioactivity in animals provided for 5 months with [75Se]selenite as the main dietary source of Se. Equilibration of the animals to a constant specific activity of 75Se allowed the measurement of 75Se to be used as a specific elemental assay for Se. Skeletal muscle, liver and blood accounted for 73% of the whole-body Se and 95% of the total Se-dependent glutathione peroxidase activity. Over 80% of the whole-body Se was in protein in the form of the selenoamino acid, selenocysteine. All other forms of Se that were measured accounted for less than 3% of the whole-body Se. The Se in protein was distributed in seven subunit sizes and nine chromatographic forms. The Se in glutathione peroxidase accounted for one-third of the whole-body Se. These results show that the main use of dietary Se, as selenite, in rats is for the synthesis of selenocysteine-containing proteins. Furthermore, the presence of two-thirds of the whole-body Se in nonglutathione peroxidase, selenocysteine-containing proteins suggests that there may be other important mammalian selenoenzymes besides glutathione peroxidase.
AB - The form and distribution of selenium (Se) in proteins from selected tissues of the rat were studied by measuring 75Se radioactivity in animals provided for 5 months with [75Se]selenite as the main dietary source of Se. Equilibration of the animals to a constant specific activity of 75Se allowed the measurement of 75Se to be used as a specific elemental assay for Se. Skeletal muscle, liver and blood accounted for 73% of the whole-body Se and 95% of the total Se-dependent glutathione peroxidase activity. Over 80% of the whole-body Se was in protein in the form of the selenoamino acid, selenocysteine. All other forms of Se that were measured accounted for less than 3% of the whole-body Se. The Se in protein was distributed in seven subunit sizes and nine chromatographic forms. The Se in glutathione peroxidase accounted for one-third of the whole-body Se. These results show that the main use of dietary Se, as selenite, in rats is for the synthesis of selenocysteine-containing proteins. Furthermore, the presence of two-thirds of the whole-body Se in nonglutathione peroxidase, selenocysteine-containing proteins suggests that there may be other important mammalian selenoenzymes besides glutathione peroxidase.
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U2 - 10.1016/0162-0134(85)83011-7
DO - 10.1016/0162-0134(85)83011-7
M3 - Article
C2 - 3156209
AN - SCOPUS:0021992060
VL - 23
SP - 77
EP - 92
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
SN - 0162-0134
IS - 2
ER -