scholarly journals Three immunoidentical cytochromes P-450 from liver microsomes of phenobarbital-treated rats

1983 ◽  
Vol 215 (1) ◽  
pp. 83-89 ◽  
Author(s):  
H Sakai ◽  
Y Hino ◽  
S Minakami

Three forms of cytochrome P-450 were purified to homogeneity from liver microsomes of Wistar-strain rats treated with phenobarbital. They had minimum mol.wts. of 52 000, 53 000 and 54 000 as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and are designated as P-450(L), P-450(M) and P-450(H) respectively. They were shown to be immunoidentical by Ouchterlony double-diffusion analysis. Several criteria, such as isoelectric points, substrate specificities and sensitivities to tryptic digestion, however, indicated that these cytochromes are distinct isoenzymes of cytochrome P-450. Whereas P-450(L) was highly active on various substrates, P-450(H) had generally low catalytic activities, except on aminopyrine. The cytochromes purified by immunoaffinity chromatography using anti-P-450(L) showed a marked variation in their distribution depending on the strain and colony of rat. Limited tryptic digestion of P-450(H) gave one tryptic peptide showing the same mobility as P-450(L) by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and their primary structures were very similar. The result suggests a possibility that such limited proteolysis is involved in the post-translational modification of the cytochrome or its destruction.

2018 ◽  
Vol 26 (2) ◽  
pp. 058
Author(s):  
Anna P. Roswiem ◽  
Triayu Septiani

<em>Bahan<strong> </strong>baku untuk membuat baso adalah daging hewan, pada umumnya dari daging sapi, ayam, ikan dan babi. Di beberapa daerah di Indonesia terjadi kasus baso tikus. Tujuan penelitian ini adalah menguji ada tidaknya kandungan daging tikus pada produk baso yang dijual di pasar Cempaka Putih-Kecamatan Kramat Jakarta Pusat dan di pedagang baso atau mie baso di sekitar kampus Universitas YARSI Jakarta. Daging adalah protein salah satu metode untuk mengidentifikasi protein adalah metode Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE).<strong> </strong>Hasil penelitian menunjukkan bahwa dari 6 sampel baso terindikasi ada 2 sampel baso dengan nomor 1 dan 5 yang dibuat dari campuran daging sapi dan tikus; ada 1 sampel baso dengan nomor 6 yang terbuat dari daging tikus; dan 2 sampel baso dengan nomor 2 dan 3 yang terbuat dari campuran sapi  dan babi, dan hanya 1 sampel baso dengan nomor sampel 4 yang benar-benar terbuat dari daging sapi.</em>


1983 ◽  
Vol 213 (1) ◽  
pp. 225-234 ◽  
Author(s):  
N Lambert ◽  
R B Freedman

Protein disulphide-isomerase from bovine liver was purified to homogeneity as judged by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, two-dimensional electrophoresis and N-terminal amino acid analysis. The preparative procedure, a modification of that of Carmichael, Morin & Dixon [(1977) J. Biol. Chem. 252, 7163-7167], is much faster and higher-yielding than previous procedures, and the final purified material is of higher specific activity. The enzyme has Mr 57 000 as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, both in the presence and in the absence of thiol compounds. Gel-filtration studies on Sephadex G-200 indicate an Mr of 107 000, suggesting that the native enzyme is a homodimer with no interchain disulphide bonds. Ultracentrifugation studies give a sedimentation coefficient of 3.5S, implying that the enzyme sediments as the monomer. The isoelectric point, in the presence of 8 M-urea, is 4.2, and some microheterogeneity is detectable. The amino acid composition is comparable with previous analyses of this enzyme from bovine liver and of other preparations of thiol:protein disulphide oxidoreductases whose relation to protein disulphide-isomerase has been controversial. The enzyme contains a very high proportion of Glx + Asx residues (27%). The N-terminal residue is His. The pure enzyme has a very small carbohydrate content, determined as 0.5-1.0% by the phenol/H2SO4 assay. Unless specific steps are taken to remove it, the purified enzyme contains a small amount (5 mol/mol of enzyme) of Triton X-100 carried through the purification.


1981 ◽  
Vol 27 (1) ◽  
pp. 72-75 ◽  
Author(s):  
K. Chaudhuri ◽  
M. Maiti

The structural polypeptides of the cholera bacteriophage [Formula: see text] have been analysed by sodium dodecyl sulphate – polyacrylamide gel electrophoresis. Eight different polypeptides were identified. The apparent molecular weights of the polypeptides were 143 000, 96 500, 68 000, 53 000, 37 500, 29 500, 21 000, and 13 500, respectively. The percentage of total protein corresponding to each polypeptide was estimated.


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