scholarly journals Purification and characterization of a labile rat glutathione transferase of the Mu class

1989 ◽  
Vol 260 (3) ◽  
pp. 789-793 ◽  
Author(s):  
A Kispert ◽  
D J Meyer ◽  
E Lalor ◽  
B Coles ◽  
B Ketterer

A labile GSH transferase homodimer termed 11-11 was purified from rat testis by GSH-agarose affinity chromatography followed by anion-exchange f.p.l.c. The enzyme is unstable in the absence of thiol(s) and has relatively low affinity for both 1-chloro-2,4-dinitrobenzene (Km 4.4 mM) and GSH (Km(app.) 4.4mM). Its mobility on SDS/polyacrylamide-gel electrophoresis is slightly less than that of subunits 3 and 4 and its pI is 5.2. Subunit 11 has a blocked N-terminal amino acid residue, but after CNBr cleavage fragments accounting for 113 amino acid residues were sequenced and showed 65% homology with corresponding sequences in subunit 4, indicating that it is a member of the Mu family. GSH transferase 11 is a major isoenzyme in testis, epididymis, prostate and brain and present at lower concentrations in other tissues.

1991 ◽  
Vol 275 (2) ◽  
pp. 541-543 ◽  
Author(s):  
J Hofsteenge ◽  
A Vincentini ◽  
S R Stone

A recombinant pig ribonuclease inhibitor (delta r-RI) lacking 90 or 93 N-terminal amino acid residues was isolated from a preparation of recombinant inhibitor. The kinetic parameters for the inhibition of ribonuclease A by delta r-RI were determined and found to be only slightly altered in comparison with the full-length inhibitor. The deletion did, however, affect the surface properties of RI. The results are discussed in relation to those obtained by Lee & Vallee [(1990) Proc. Natl. Acad. Sci. U.S.A. 87, 1879-1883].


1973 ◽  
Vol 74 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Michel Chrétien ◽  
Claude Gilardeau

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.


1988 ◽  
Vol 255 (3) ◽  
pp. 971-975 ◽  
Author(s):  
C Di Ilio ◽  
A Aceto ◽  
R Piccolomini ◽  
N Allocati ◽  
A Faraone ◽  
...  

Three forms of glutathione transferase (GST) with pI values of 6.0, 6.4 and 7.3 were isolated from Proteus mirabilis AF 2924 by glutathione-affinity chromatography followed by isoelectric focusing, and their structural, kinetic and immunological properties were investigated. Upon SDS/polyacrylamide-slab-gel electrophoresis, all forms proved to be composed of two subunits of identical (22,500) Mr. GST-6.0 and GST-6.4 together account for about 95% of the total activity, whereas GST-7.3 is present only in trace amounts. Extensive similarities have been found between GST-6.0 and GST-6.4. These include subunit molecular mass, amino acid composition, substrate specificities and immunological characteristics. GST-7.3 also cross-reacted (non-identity) with antisera raised against bacterial GST-6.0. None of the antisera raised against a number of human, rat and mouse GSTs cross-reacted with the bacterial enzymes, indicating major structural differences between them and the mammalian GSTs. This conclusion is further supported by c.d. spectra.


1985 ◽  
Vol 63 (8) ◽  
pp. 824-829
Author(s):  
C. C. Liew ◽  
Peter C. Hentzen ◽  
Isaac Bekhor

Extraction of chicken reticulocyte and erythrocyte chromatins with 2 M NaCl yields a small fraction (about 5%) of the total DNA which is very tightly bound to a class of nonhistone chromatin proteins (DNA–P). This DNA fraction has previously been shown to be significantly enriched in active gene sequences. The proteins associated with reticulocyte and erythrocyte DNA–P were analyzed by two-dimensional gel electrophoresis. Reticulocyte DNA–P yield predominantly three major proteins, designated G1, G2, and G3 with relative masses of 80 000, 50 000, and 58 000, respectively. Erythrocyte DNA–P show only two proteins which appear to be similar to the reticulocyte G1 and G2 proteins, except in much reduced quantities as revealed by two-dimensional polyacrylamide gel electrophoresis. Amino acid analysis of the three reticulocyte proteins revealed that the ratio of acidic to basic amino acid residues increased in the order G1 < G2 < G3, while the respective isoelectric points also increased in that order.


1989 ◽  
Vol 261 (3) ◽  
pp. 973-977 ◽  
Author(s):  
L D Smith ◽  
N Budgen ◽  
S J Bungard ◽  
M J Danson ◽  
D W Hough

Glucose dehydrogenase was purified to homogeneity from the thermoacidophilic archaebacterium Thermoplasma acidophilum. The enzyme is a tetramer of polypeptide chain Mr 38,000 +/- 3000, it is catalytically active with both NAD+ and NADP+ cofactors, and it is thermostable and remarkably resistant to a variety of organic solvents. The amino acid composition was determined and compared with those of the glucose dehydrogenases from the archaebacterium Sulfolobus solfataricus and the eubacteria Bacillus subtilis and Bacillus megaterium. The N-terminal amino acid sequence of the Thermoplasma acidophilum enzyme was determined to be: (S/T)-E-Q-K-A-I-V-T-D-A-P-K-G-G-V-K-Y-T-T-I-D-M-P-E.


1975 ◽  
Author(s):  
B. E. Ly ◽  
P. Kierulf

Fibrinogen preparations with increasing contents of iodine, ranging from 0.2 to 20 atoms of iodine per molecule fibrinogen, were obtained with the ICl method. Aggregation and shortening of the thrombin clotting time occurred when the content of iodine exceeded 3 atoms per molecule.Upon the action of thrombin, the increase in N-terminal glycine, reflecting fibrin formation, was almost identical in native and iodinated fibrinogen. At visible gelation, however, decreased amounts of N-terminal glycine were found in heavily iodinated fibrinogen, thus indicating enhanced fibrin polymerization. N-terminal analysis of heavily iodinated fibrinogen demonstrated a deficiency in N-terminal tyrosine concomitantly with the apparance of a new N-terminal amino acid, identified as mono-iodo-tyrosine.Polyacrylamide gel electrophoresis at pH 8.9 revealed an increase in mobility following extensive iodination, but no shift in the isoelectric point was observed upon isofocusing.Neither clottability nor the behaviour of fibrinogen and its subunit polypeptide chains on SDS-gel electrophoresis was affected by iodination.


1974 ◽  
Vol 141 (3) ◽  
pp. 633-639 ◽  
Author(s):  
Bryan J. Starkey ◽  
David Snary ◽  
Adrian Allen

1. The mucoprotein from pig gastric mucus has been purified by equilibrium centrifugation in a CsCl gradient. 2. This procedure removes the non-covalently bound protein, which is closely associated with the mucoprotein and not easily removed from it by gel filtration. 3. The purified mucoprotein is separable by gel filtration into a high-molecular-weight mucoprotein A (mol.wt. 2.3×106) and a low-molecular-weight mucoprotein B/C (mol.wt. 1.15×106). 4. These two mucoproteins have the same chemical analysis namely fucose 11.3%, galactose 26%, glucosamine 19.5%, galactosamine 8.3% and protein 13.6%. 5. Mucoprotein A contains 3.1% ester sulphate. 6. These mucoproteins are isolated without enzymic digestion and have a higher protein content than the blood-group-substance mucoproteins from proteolytic digestion of gastric mucus. Detailed amino acid analysis shows that the extra protein in the non-enzymically digested material is composed of amino acids other than serine and threonine. 7. Mucoproteins A and B/C contain respectively 130 and 9 half-cystine residues per molecule of which about 78 and 6 residues are involved in disulphide linkages. 8. Cleavage of these disulphide linkages by mercaptoethanol splits both mucoproteins into four equally sized subunits of mol.wt. 5.2×105for mucoprotein A and 2.8×104for mucoprotein B/C. 9. The sole N-terminal amino acid of mucoprotein A is aspartic acid, whereas mucoprotein B/C has several different N-terminal amino acid residues.


1983 ◽  
Vol 209 (1) ◽  
pp. 151-157 ◽  
Author(s):  
C J Bailey ◽  
P D Turner

Tryptophan synthase was purified from baker's yeast. The purified enzyme exhibited one band on polyacrylamide-gel electrophoresis, had no detectable N-terminal amino acid and C-terminal alanine. The amino acid composition was close to that predicted by recent studies on the DNA sequence of the structural gene for the enzyme. Kinetic parameters for the following three activities were measured: indole-serine condensation, indolylglycerol phosphate lyase and the overall reaction of serine with 1-(indol-3-yl)glycerol 3-phosphate. The Km for indole was much lower than suggested by previous investigations, and the value of 11 microM was measured by a fluorimetric assay.


1974 ◽  
Vol 143 (3) ◽  
pp. 575-586 ◽  
Author(s):  
Christopher W. Wharton

1. Purified stem bromelain (EC 3.4.22.4) was eluted from Sephadex G-100 as a single peak. The specific activity across the elution peak was approximately constant towards p-nitrophenyl hippurate but increased with elution volume with N2-benzoyl-l-arginine ethyl ester as substrate. 2. The apparent molecular weight, determined by elution analysis on Sephadex G-100, is 22500±1500, an anomalously low value. 3. Purified stem bromelain was eluted from CM-cellulose CM-32 as a single peak and behaved as a single species during column electrophoresis on Sephadex G-100. 4. Purified stem bromelain migrates as a single band during polyacrylamide-gel electrophoresis under a wide variety of conditions. 5. The molecular weight determined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate is 28500±1000. 6. Sedimentation-velocity and equilibrium-ultracentrifugation experiments, under a variety of conditions, indicate that bromelain is an apparently homogeneous single peptide chain of mol.wt. 28400±1400. 7. The N-terminal amino acid composition is 0.64±0.04mol of valine and 0.36±0.04mol of alanine per mol of enzyme of mol.wt. 28500. (The amino acid recovery of the cyanate N-terminal amino acid analysis was standardized by inclusion of carbamoyl-norleucine at the cyclization stage.) 8. The pH-dependence of the Michaelis parameters of the bromelain-catalysed hydrolysis of N-benzyloxycarbonyl-l-phenylalanyl-l-serine methyl ester was determined. 9. The magnitude and pH-dependence of the Michaelis parameters have been interpreted in terms of the mechanism of the enzyme. 10. The enzyme is able to bind N-benzyloxycarbonyl-l-phenylalanyl-l-serine methyl ester relatively strongly but seems unable to make use of the binding energy to promote catalysis.


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