scholarly journals Co-purification of galactosyltransferases from chick-embryo liver

1985 ◽  
Vol 227 (2) ◽  
pp. 573-582 ◽  
Author(s):  
K Furukawa ◽  
S Roth

Two galactosyltransferases with nearly identical Mr values were purified 5000-7000-fold from microsomal membranes of chick-embryo livers by using several affinity columns. One enzyme transfers galactose from UDP-galactose to form a β-(1→4)-linkage to GlcNAc (N-acetylglucosamine) or AsAgAGP [asialo-agalacto-(alpha 1-acid glycoprotein)]. The other enzyme forms a β-(1→3)-linkage to AsOSM [asialo-(ovine submaxillary mucin)]. Both enzymes were solubilized (85%) from a microsomal pellet by using 1% Triton X-100 in 0.1 M-NaCl. The supernatant activities were subjected to DEAE-Sepharose chromatography and four affinity columns: UDP-hexanolamine-Sepharose, alpha-lactalbumin-Sepharose, GlcNAc-Sepharose and either AsAgAGP-Sepharose or AsOSM-Sepharose. The AsAgAGP enzyme [(1→4)-transferase] and the AsOSM enzyme [(1→3)-transferase] behave identically on the DEAE-Sepharose and UDP-hexanolamine-Sepharose columns, and similarly on the alpha-lactalbumin-Sepharose column. Final separation of the two enzymes, however, could only be achieved on affinity columns of their immobilized respective acceptors. Both purified enzymes migrate as a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis after silver staining, and both have an apparent Mr of 68 000. The enzymes were radioiodinated and again subjected to sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Radioautographic analyses showed only one, intensely radioactive, band. Activity stains performed for both transferases after cellulose acetate electrophoresis indicate that, with this system too, both activities have identical mobilities, and co-migrate, as well, with the major, silver-stained, protein band. Kinetic studies with the purified enzymes show that the Km value for GlcNAc, for the (1→4)-transferase, is 4mM; for the (1→3)-transferase the Km value for AsOSM is 5mM, in terms of GalNAc (N-acetylgalactosamine) equivalents. Both enzymes have a Km value of 25 microM for UDP-galactose.

1980 ◽  
Vol 185 (1) ◽  
pp. 227-237 ◽  
Author(s):  
Y Nagamatsu ◽  
T Oka

alpha-Lactalbumin was purified to apparent homogeneity from mouse milk by combined use of gel filtration, chromatography on DEAE-cellulose and hydroxyapatite, and concanavalin A-Sepharose affinity chromatography. Mouse alpha-lactalbumin exists in several species with different charges and in two molecular-size forms. The smaller form, which constituted over 90% of total alpha-lactalbumin, included two major and two minor species, each of which showed different electrophoretic mobility on polyacrylamide-gel electrophoresis, but gave the same single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis in two different buffer systems and over the range 10-15% acrylamide concentrations. The molecular weight was estimated as 14 100. The two major species of the smaller form had the same amino acid composition and contained no significant amount of carbohydrate. The larger form of alpha-lactalbumin, consisting of two species with different charges, was present in a small amount (less than 10%) in the milk and was isolated by its ability to interact with concanavalin A-Sepharose. Each of the two species also gave the same single band of apparent mol.w.t 18 500 on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. However, this value may be anomalous, since this larger form appears to be glycosylated, and glycoproteins can behave anomalously on sodium dodecyl sulphate/polyacrylamide gels by binding less sodium dodecyl sulphate. All species of mouse alpha-lactalbumin from milk were active in the lactose synthase reaction and showed identical immunological properties, as determined by the mono-specific antibody prepared against the small major species. The presence of both the larger and the smaller forms, each in a percentage concentration similar to that found in milk, was also demonstrated in alpha-lactalbumin induced by hormones in organ cultureof pregnant-mouse mammary gland.


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.


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