Study of chromium-containing proteins in subcellular fractions of rat liver by enriched stable isotopic tracer technique and gel filtration chromatography.
Ten male Wistar rats were intravenously injected with a single approximately physiological dose of enriched stable isotopic Cr-50 tracer solution (200 ng (50)Cr(3+)/100 g body wt). The fundamental distribution patterns of the chromium-containing proteins in the nucleic, mitochondrial, lysosomal, microsomal, and cytosolic subcellular fractions of the rat liver were investigated by means of Sephadex G-100 gel chromatography combined with neutron activation analysis via (50)Cr (n, gamma) (51)Cr reaction. In total, nine kinds of Cr-containing proteins were found in the five subcellular fractions, whose relative molecular masses were 96.6+/-6.2, 68.2+/-1.4, 57.9+/-4.7, 36.6+/-1.2, 24.2+/-1.8, 14.0+/-1.5, 8.8+/-0.6, 6.9+/-0.4, and 4.2+/-0.4 kDa. Approximately 64.5% of Cr proteins accumulated in the cytosolic fraction. The second enriched part was the nucleic fraction; about 12.2% Cr proteins were stored in this section. The 4.2-kDa molecular mass might contain the so-called low molecular weight chromium-containing substance; however, in this research, it was only observed in the mitochondria, lysosome, and microsome. In the mitochondrial fraction, most of the Cr proteins were present as relatively low molecular weight substances: about 56% of chromium-containing proteins had molecular masses < or =6.9 kDa. Nevertheless, more than 69% of Cr-containing proteins were observed with molecular masses > or =57.9 kDa in the liver cytosolic fraction.
Feng
Weiyue
W
Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, 100039 Beijing, P.R. China. fengwy@mail.ihep.ac.cn
Li
Bai
B
Liu
Jing
J
Chai
Zhifang
Z
Zhang
Peiqun
P
Gao
Yuxi
Y
Zhao
Jiujiang
J
D000818:Animals; D002458:Cell Fractionation; D002850:Chromatography, Gel; D002857:Chromium / Q000378:metabolism*; D003600:Cytosol / Q000737:chemistry; D008099:Liver / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure; D008297:Male; D008667:Metalloproteins / Q000032:analysis / Q000378:metabolism*; D008970:Molecular Weight; D015388:Organelles / Q000737:chemistry; D011849:Radioactive Tracers; D011868:Radioisotopes / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar
D008667:Metalloproteins; D011849:Radioactive Tracers; D011868:Radioisotopes; D002857:Chromium