scholarly journals Isolation and partial characterization of magnesium ion-and calcium ion-dependent adenosine triphosphatase activity from bovine brain microsomal fraction

1979 ◽  
Vol 181 (2) ◽  
pp. 321-330 ◽  
Author(s):  
Torben Særmark ◽  
Hans Vilhardt

Microsomal fraction was prepared by ultracentrifugation of homogenates of cortical tissue from bovine brains. The preparation displayed ATPase (adenosine triphosphatase) activity in the presence of Mg2+ (6.4μmol of Pi/h per mg of protein) and Ca2+ (3.4μmol of Pi/h per mg of protein). Kinetic analysis of the activation of the enzyme preparation by Ca2+ resulted in the demonstration of two apparent Km values for Ca2+ (6.0×10−8m and 1.2×10−6m). Treatment of the microsomal membranes with Triton X-100 resulted in solubilization of the ATPase, though with some loss of activity. The solubilized microsomal proteins were incorporated into liposomes. By incubation of the liposomes in media containing 45Ca2+ an ATP-dependent uptake of Ca2+ was demonstrated. The solubilized preparation was subjected to preparative isoelectric focusing in granulated gel beds. Two distinct peaks of Mg2+- and Ca2+-dependent ATPase activity were observed at pH4.8 (peak 4.8) and at pH6.3 (peak 6.3). The material isolated in peaks 4.8 and 6.3 was focused in polyacrylamide gel with pH gradients. The material corresponding to peak 4.8 consisted of a single protein, whereas peak 6.3 contained one major and at least one minor protein. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis confirmed these results and indicated that the major component of peak 4.8 and the protein of peak 6.3 both had a molecular weight of 105000. The material in peaks 4.8 and 6.3 was assayed for ATPase activity in the presence of various concentrations of Ca2+. Kinetic analysis of the results for peak 4.8 demonstrated an apparent Km value for Ca2+ of 4.1×10−8m. The enzyme isolated at pH6.3 had an apparent Km value of 3.8×10−6m. However, when the material from peak 4.8 was incubated in the presence of 1mm-Mg2+ the ATPase could not be activated by Ca2+.

1979 ◽  
Vol 182 (2) ◽  
pp. 617-619 ◽  
Author(s):  
V L Drutsa ◽  
I A Kozlov ◽  
Y M Milgrom ◽  
Z A Shabarova ◽  
N I Sokolova

The reaction of the mixed anhydride of [3H]ATP and mesitylenecarboxylic acid and soluble mitochondrial adenosine triphosphatase is accompanied by the covalent binding of one molecule of the inhibitor to a molecule of the enzyme and results in the inhibition of adenosine triphosphatase activity by more than 90%. The electrophoresis of adenosine triphosphatase modified by reaction with the mixed anhydride of [3H]ATP and mesitylenecarboxylic acid in polyacrylamide gel in the presence of sodium dodecyl sulphate showed that the inhibitor is bound to the beta-subunit of the enzyme. The results suggest that ATP may also bind to the beta-subunit of the adenosine triphosphatase with its triphosphate moiety.


1984 ◽  
Vol 219 (3) ◽  
pp. 899-904 ◽  
Author(s):  
R Barth ◽  
E G Afting

The purification of cathepsin D from pig uterus by two-step affinity chromatography on concanavalin A- and pepstatin-Sepharose was described previously [Afting & Becker (1981) Biochem. J. 197, 519-522]. In this paper, chemical and physical properties of the proteinase are presented. The purified enzyme showed three bands on SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis, one main band corresponding to an Mr of 31 000 and two minor bands with Mr values of 43 000 and 15 000 respectively. Gel filtration on Bio-gel P-150 and sedimentation-diffusion equilibrium studies give an Mr for the main band of about 35 000. The pI of the enzyme was determined to be 7.2. Haemoglobin was the best substrate, with a Km value of 6.4 X 10(-6)M. It was hydrolysed with a pH optimum between 3.0 and 3.3 for a substrate concentration of 100 microM. The proteinase was stable over the pH range of 3.5-6.5. At pH 6 the enzyme showed stability up to a temperature of 50 degrees C; at pH 3 the activity was already decreased below 40 degrees C. Carbohydrate studies resulted in the staining of all three bands on an SDS/polyacrylamide gel by thymol/H2SO4. After treatment with endo-beta-N-acetylglucosaminidase H, all three bands were shifted to a region of lower Mr. Of various inhibitors tested, only pepstatin was strongly inhibiting, with a Ki of 2.1 X 10(-9)M.


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.


1978 ◽  
Vol 175 (1) ◽  
pp. 63-72 ◽  
Author(s):  
W Schook ◽  
C Ores ◽  
S Puszkin

alpha-Actinin isolated from bovine brain migrated on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis like muscle alpha-actinin with an apparent mol.wt. of 100000 and cross-reacted with antibodies to muscle alpha-actinin. Brain alpha-actinin modulated actin-myosin Mg2+-activated adenosine triphosphatase activity and, when bound by polystyrene particles, was found to bind muscle actin and tropomyosin from solution. Brain alpha-actinin, in conjunction with the other components of the contractile and relaxing complex, may play a role in the release of neurotransmitters from synaptic vesicles.


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>


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