scholarly journals Purification and characterization of mouse α-lactalbumin and preparation of its antibody

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.

1983 ◽  
Vol 215 (3) ◽  
pp. 617-625 ◽  
Author(s):  
T Friedberg ◽  
U Milbert ◽  
P Bentley ◽  
T M Guenther ◽  
F Oesch

A hitherto unknown cytosolic glutathione S-transferase from rat liver was discovered and a method developed for its purification to apparent homogeneity. This enzyme had several properties that distinguished it from other glutathione S-transferases, and it was named glutathione S-transferase X. The purification procedure involved DEAE-cellulose chromatography, (NH4)2SO4 precipitation, affinity chromatography on Sepharose 4B to which glutathione was coupled and CM-cellulose chromatography, and allowed the isolation of glutathione S-transferases X, A, B and C in relatively large quantities suitable for the investigation of the toxicological role of these enzymes. Like glutathione S-transferase M, but unlike glutathione S-transferases AA, A, B, C, D and E, glutathione S-transferase X was retained on DEAE-cellulose. The end product, which was purified from rat liver 20 000 g supernatant about 50-fold, as determined with 1-chloro-2,4-dinitrobenzene as substrate and about 90-fold with the 1,2-dichloro-4-nitrobenzene as substrate, was judged to be homogeneous by several criteria, including sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, isoelectric focusing and immunoelectrophoresis. Results from sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration indicated that transferase X was a dimer with Mr about 45 000 composed of subunits with Mr 23 500. The isoelectric point of glutathione S-transferase X was 6.9, which is different from those of most of the other glutathione S-transferases (AA, A, B and C). The amino acid composition of transferase X was similar to that of transferase C. Immunoelectrophoresis of glutathione S-transferases A, C and X and precipitation of various combinations of these antigens by antisera raised against glutathione S-transferase X or C revealed that the glutathione S-transferases A, C and X have different electrophoretic mobilities, and indicated that transferase X is immunologically similar to transferase C, less similar to transferase A and not cross-reactive to transferases B and E. In contrast with transferases B and AA, glutathione S-transferase X did not bind cholic acid, which, together with the determination of the Mr, shows that it does not possess subunits Ya or Yc. Glutathione S-transferase X did not catalyse the reaction of menaphthyl sulphate with glutathione, and was in this respect dissimilar to glutathione S-transferase M; however, it conjugated 1,2-dichloro-4-nitrobenzene very rapidly, in contrast with transferases AA, B, D and E, which were nearly inactive towards that substrate.(ABSTRACT TRUNCATED AT 400 WORDS)


1984 ◽  
Vol 222 (1) ◽  
pp. 265-268 ◽  
Author(s):  
S E Marcus ◽  
J Burgess ◽  
P R Maycox ◽  
D J Bowles

Maturation events have been studied in developing jackbean (Canavalia ensiformis) cotyledons by using a combination of analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, overlays with 125I-concanavalin A (Con A) and the use of anti-(Con A) after Western transfer. The number of polypeptides recognized by 125I-Con A varies during maturation, until at maturity only one remains. Several molecular forms of the lectin occur during development; one, corresponding to Mr 33 000 and found only in immature seeds, interacts with 125I-Con A, suggesting that it is glycosylated.


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.


1985 ◽  
Vol 226 (1) ◽  
pp. 147-153 ◽  
Author(s):  
D B Harper ◽  
J T Kennedy

An enzyme catalysing the O-methylation of isobutyraldoxime by S-adenosyl-L-methionine was isolated from Pseudomonas sp. N.C.I.B. 11652. The enzyme was purified 220-fold by DEAE-cellulose chromatography, (NH4)2SO4 fractionation, gel filtration on Sephadex G-100 and chromatography on calcium phosphate gel. Homogeneity of the enzyme preparation was confirmed by isoelectric focusing on polyacrylamide gel and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The enzyme showed a narrow pH optimum at 10.25, required thiol-protecting agents for activity and was rapidly denatured at temperatures above 35 degrees C. The Km values for isobutyraldoxime and S-adenosyl-L-methionine were respectively 0.24 mM and 0.15 mM. Studies on substrate specificity indicated that attack was mainly restricted to oximes of C4-C6 aldehydes, with preference being shown for those with branching in the 2- or 3-position. Ketoximes were not substrates for the enzyme. Gel filtration on Sephadex G-100 gave an Mr of 84 000 for the intact enzyme, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated an Mr of 37 500, suggesting the presence of two subunits in the intact enzyme. S-Adenosylhomocysteine was a powerful competitive inhibitor of S-adenosylmethionine, with a Ki of 0.027 mM. The enzyme was also susceptible to inhibition by thiol-blocking reagents and heavy-metal ions. Mg2+ was not required for maximum activity.


1977 ◽  
Vol 167 (3) ◽  
pp. 685-692 ◽  
Author(s):  
David B. Harper

1. A strain of the fungus Fusarium solani able to use benzonitrile as sole source of carbon and nitrogen was isolated by elective culture. 2. Respiration studies indicate that the nitrile, after degradation to benzoate, is catabolized via catechol or alternatively via p-hydroxybenzoate and 3,4-dihydroxybenzoate. 3. Cell-free extracts of benzonitrile-grown cells contain an enzyme mediating the conversion of benzonitrile into benzoate and ammonia. 4. The nitrilase enzyme was purified by DEAE-cellulose chromatography, (NH4)2SO4 precipitation and gel filtration on Sephadex G-200. The homogeneity of the purified enzyme preparation was confirmed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and isoelectric focusing on polyacrylamide gel. 5. The enzyme showed a broad pH optimum between pH7.8 and 9.1 and a Km with benzonitrile as substrate of 0.039mm. The activation energy of the reaction deduced from an Arrhenius plot was 48.4kJ/mol. 6. The enzyme was susceptible to inhibition by thiol-specific reagents and certain heavy metal ions. 7. Gel filtration gave a value of 620000 for the molecular weight of the intact enzyme. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis demonstrated that the enzyme was composed of eight subunits of mol.wt. 76000. 8. Rates of enzymic attack on various substrates indicated that the nitrilase has a fairly broad specificity and that the fungus probably plays an important role in the biodegradation of certain nitrilic herbicides in the environment.


1980 ◽  
Vol 187 (2) ◽  
pp. 437-446 ◽  
Author(s):  
Lilian M. Y. Lee ◽  
Antonieta K. Salvatore ◽  
Peter R. Flanagan ◽  
Gordon G. Forstner

Maltase/glucoamylase from the rat intestinal brush-border membrane was solubilized by homogenization of the intestinal mucosa in buffer containing 0.5% Triton X-100. After removal of the detergent with butan-1-ol, the enzyme was purified by chromatography on Sepharose 4B and DEAE-cellulose. The final specific activity was 70.3 units/mg of protein in six preparations, comparing favourably with the specific activity of 65.0 units/mg of protein of a pure papain-solubilized maltase/glucoamylase previously isolated and characterized by us [Flanagan & Forstner (1978) Biochem. J.173, 553–563]. The two enzymes were compared. Both migrated as single bands with the same mobility on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, were eluted at the same volume from Sepharose 4B, and had the same sedimentation pattern in mannitol gradients. The amino acid composition was similar; content of total apolar residues differed by 1.0mol%. Antibodies prepared against either enzyme gave identical precipitin lines with each. Neither enzyme bound tritiated Triton X-100. The only difference noted was the tendency of the detergent-solubilized enzyme to aggregate on storage, whereas the papain-solubilized enzyme remained unchanged. Both enzymes had two N-termini, glycine and arginine. When the two enzymes were dissociated by boiling in sodium dodecyl sulphate, each exhibited the same five species on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Single N-termini were found in the two smaller species, 1 (glycine) and 2 (arginine), whereas larger species (3–5) had both N-terminal amino acids. Both the Triton- and papain-solubilized enzymes appear to be oligomers of species 1 and 2, indicating that the native enzyme contains two subunit types. Aggregation in aqueous solutions does not depend on a proteolytically susceptible peptide fragment at the N-terminus of either subunit.


1976 ◽  
Vol 155 (3) ◽  
pp. 653-660 ◽  
Author(s):  
J M Trépanier ◽  
L E Seargeant ◽  
R A Stinson

Alkaline phosphatase from human liver was purified to homogeneity. The purification procedure included solubilization with butanol, fractionation with acetone, and chromatography on concanavalin A-Sepharose, DEAE-cellulose, Sephadex G-200 and DEAE-Sephadex. Purity was established by standard and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The isoelectric point of the protein was determined to be 4.0. Sephadex-gel filtration gave a mol.wt. of 146000, although a higher value was obtained in the presence of 100mM-NaC1. The subunit mol.wt. 76700, was determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Neuraminidase treatment resulted in two enzyme-activity bands on isoelectric-focused gels with isoelectric points of 6.6 and 6.8. The desialylated enzyme gave only one protein band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with a subunit molecular weight indistinguishable from that of the non-neuraminidase-treated protein. The desialylated enzyme was more readily denatured by sodium dodecyl sulphate in the presence of mercaptoethanol than was the native enzyme.


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.


1984 ◽  
Vol 219 (3) ◽  
pp. 1009-1015 ◽  
Author(s):  
H C Parkes ◽  
J L Stirling ◽  
P Calvo

beta-N-Acetylhexosaminidase from boar epididymis was separated into two forms, A and B, on DEAE-cellulose. Both these forms were excluded from Sepharose S-200 and had apparent Mr values of 510 000 on gradient gel electrophoresis under non-denaturing conditions. Affinity chromatography on 2-acetamido-N-(6-aminohexanoyl)-2-deoxy-beta-D-glucopyranosylam ine coupled to CNBr-activated Sepharose 4B was used to separate and purify beta-N-acetylhexosaminidases A and B that had specific activities of 115 and 380 mumol/min per mg of protein respectively. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of denatured beta-N-acetylhexosaminidase A gave a single major component of Mr 67 000. beta-N-Acetylhexosaminidase B also had this component, and in addition had polypeptides of Mr 29 000 and 26 000. All these polypeptides were glycosylated. Antiserum to the B form precipitated form A from solution and reacted with the 67 000-Mr component or form A after electrophoretic transfer from sodium dodecyl sulphate/polyacrylamide gels to nitrocellulose sheets. The 67 000-Mr components of forms A and B yielded identical peptide maps when digested with Staphylococcus aureus V8 proteinase, and the 29 000-Mr and 26 000-Mr components in form B may be related to the 67 000-Mr polypeptide.


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