scholarly journals The purification and properties of isocitrate lyase from Chlorella

1967 ◽  
Vol 105 (1) ◽  
pp. 409-416 ◽  
Author(s):  
P. C. L. John ◽  
P. J. Syrett

1. Isocitrate lyase (threo-ds-isocitrate glyoxylate-lyase, EC 4.1.3.1) has been purified from acetate-adapted cells of Chlorella pyrenoidosa. 2. The final preparation was homogeneous by the criteria of sedimentation, diffusion and polyacrylamide-gel electrophoresis. 3. The sedimentation coefficient (S20,w) was 9·04×10−13sec. and the diffusion coefficient (D20,w) 4·62×10−7cm.2/sec.; from these values the molecular weight of the enzyme was calculated to be 170000 and its Stokes radius to be 4·63×10−7cm. 4. The elution of the enzyme from Sephadex G-100 was studied and estimates of molecular weight and Stokes radius were obtained from the elution data. 5. The turnover number of the enzyme was 5950moles of glyoxylate formed/min./mole of enzyme at 30°. 6. With threo-ds(+)-isocitrate as substrate, the Km of the enzyme was 0·023mm.

1969 ◽  
Vol 115 (4) ◽  
pp. 639-643 ◽  
Author(s):  
R. H. Villet ◽  
K. Dalziel

A method is described for the isolation of 6-phosphogluconate dehydrogenase from sheep liver. The product appears to be homogeneous in polyacrylamide-gel electrophoresis and in sedimentation-velocity and sedimentation-equilibrium studies in the ultracentrifuge. The molecular weight is estimated as 129000 from equilibrium sedimentation.


1993 ◽  
Vol 39 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Mohamed Blaghen ◽  
Dominique J. M. Vidon ◽  
Mohamed Said El Kebbaj

A mercuric ion-reducing flavoprotein was purified from Yersinia enterocolitica 138A14 using dye matrix affinity chromatography. The purified enzyme had a characteristic absorption spectrum similar to those of flavin compounds, and FAD was detected as a part of the purified enzyme by thin-layer chromatography. Freshly purified preparations of the enzyme showed a single band on SDS polyacrylamide gel electrophoresis with a molecular weight of 70 000. The isolated enzyme had a molecular weight of about 200 000 as determined by gel filtration and disc gel electrophoresis. These results suggest an apparently trimeric structure of the enzyme. Dithiothreitol treatment disrupted the trimer into a dimeric structure of 140 000. Along with ageing, as well as limited proteolytic digestion, the enzyme evolved to give a dimeric molecule of 105 000 composed of two identical subunits of 52 000. The combination of the purified enzyme with HgCl2, or unexpectedly with merthiolate, oxidised the NADPH, which was followed spectrophotometrically. The Km for HgCl2 was dependent on the concentration of exogenous thiol compounds. A comparison of physical properties as well as kinetic characteristics indicated that the enzyme from Y. enterocolitica 138A14 is similar to mercuric reductases isolated from other mercury-resistant bacteria.Key words: Yersinia enterocolitica, mercury resistance, mercuric reductase.


1973 ◽  
Vol 51 (11) ◽  
pp. 1551-1555 ◽  
Author(s):  
Tony C. M. Seah ◽  
A. R. Bhatti ◽  
J. G. Kaplan

At any stage of growth of a wild-type bakers' yeast, some 20% of the catalatic activity of crude extracts is not precipitable by means of antibody prepared against the typical catalase (catalase T), whose purification and properties have been previously described. Some of this catalatic activity is due to the presence of an atypical catalase (catalase A), a heme protein, with a molecular weight estimated as 170 000 – 190 000, considerably lower than that of the usual catalases (225 000 – 250 000). Preparations of catalase A were found to be homogeneous in the analytical ultracentrifuge and in polyacrylamide gel electrophoresis. Its subunit molecular weight, determined from its iron content, was 46 500, virtually the same as that of the major band obtained in gel electrophoresis in the presence of sodium dodecyl sulfate, suggesting that the native protein is tetrameric. Its specific activity is in the range of those reported for other typical catalases.


1982 ◽  
Vol 152 (2) ◽  
pp. 757-761
Author(s):  
V L Sheladia ◽  
J P Chambers ◽  
J Guevara ◽  
D J Evans

A hemagglutinin which specifically agglutinates human type A erythrocytes (mannose resistant) was isolated from the growth medium of cultures of Escherichia coli GV-12, serotype O1:H-, and purified by chromatography on Bio-Gel A-1.5 and DEAE-Sephadex A-25. The purity of the hemagglutinin was established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoelectrophoresis. N-terminus analysis indicated that only asparagine resides on the amino terminus. The native hemagglutinin is an aggregate exhibiting a sedimentation coefficient of 9.25, which corresponds to a molecular weight of approximately 200,000. The monomeric molecular weight was found to be approximately 16,300. Amino acid analysis indicated that the hemagglutinin consists of 131 residues, corresponding to a molecular weight of 13,400.


1987 ◽  
Vol 54 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Norihiro Azuma ◽  
Kunio Yamauchi

SummaryA highly glycosylated phosphoprotein (HGPP) was isolated from a human casein fraction by reversed-phase high-performance liquid chromatography. This component contained carbohydrates to ∼ 38·2% (w/w) and phosphorus to ∼ 1·6% (w/w). The molecular weight of this HGPP as estimated by sodium dodecyl sulphate–polyacrylamide gel electrophoresis ∼ 41000. Ultracentrifugal analysis revealed that the sedimentation coefficient of the HGPP was 2·6S in a 10 mM-imidazole-HCl buffer at pH 7·0 and 27 °C, but this component interacted with human κ-casein and formed a complex with s = 10·4S.


1976 ◽  
Vol 157 (2) ◽  
pp. 409-413 ◽  
Author(s):  
R K Airas ◽  
E A Hietanen ◽  
V T Nurmikko

Pantothenase (EC 3.5.1.22) from Pseudomonas fluorescens UK-1 was purified to homogeneity as judged by disc-gel electrophoresis and isoelectric focusing. The purification procedure consisted of four steps: DEAE-Sephadex chromatography, (NH4)2SO4 precipitation, hydroxyapatite chromatography and preparative polyacrylamide-gel electrophoresis. Gel filtration on Ultrogel AcA 34 was used to determine the molecular weight, and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis to study the subunit molecular weight. The enzyme appeared to be composed of two subunits with mol.wts. of approx. 50000 each. The total mol.wt. of the enzyme was thus about 100000. The isoelectric point was 4.7 at 10 degrees C.


1969 ◽  
Vol 113 (1) ◽  
pp. 131-138 ◽  
Author(s):  
U E Loening

1. The effects of changes in experimental conditions on the mobility of RNA in polyacrylamide-gel electrophoresis were investigated. 2. The linear relation between log(molecular weight) and electrophoretic mobility was shown to be independent within limits of salt or gel concentration. 3. The relative mobility of RNA with low content of guanylic acid and cytidylic acid residues was decreased in low-ionic-strength buffer. This was related to a small relative decrease in sedimentation coefficient. 4. However, Mg2+ ion caused almost no increase in mobility although it was associated with large increases in sedimentation coefficient. This suggested opposing actions of Mg2+ ion on the size and effective charge of the RNA. 5. It is concluded that the method provides a satisfactory measurement of molecular weight, which is almost independent of the nucleotide composition of RNA at moderate salt concentrations.


1992 ◽  
Vol 68 (05) ◽  
pp. 534-538 ◽  
Author(s):  
Nobuhiko Yoshida ◽  
Shingi Imaoka ◽  
Hajime Hirata ◽  
Michio Matsuda ◽  
Shinji Asakura

SummaryCongenitally abnormal fibrinogen Osaka III with the replacement of γ Arg-275 by His was found in a 38-year-old female with no bleeding or thrombotic tendency. Release of fibrinopeptide(s) by thrombin or reptilase was normal, but her thrombin or reptilase time in the absence of calcium was markedly prolonged and the polymerization of preformed fibrin monomer which was prepared by the treatment of fibrinogen with thrombin or reptilase was also markedly defective. Propositus' fibrinogen had normal crosslinking abilities of α- and γ-chains. Analysis of fibrinogen chains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system of Laemmli only revealed the presence of abnormal γ-chain with an apparently higher molecular weight, the presence of which was more clearly detected with SDS-PAGE of fibrin monomer obtained by thrombin treatment. Purified fragment D1 of fibrinogen Osaka III also seemed to contain an apparently higher molecular weight fragment D1 γ remnant on Laemmli gels, which was digested faster than the normal control by plasmin in the presence of [ethy-lenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA).


1979 ◽  
Author(s):  
M Ribieto ◽  
J Elion ◽  
D Labie ◽  
F Josso

For the purification of the abnormal prothrombin (Pt Metz), advantage has been taken of the existence in the family of three siblings who, being double heterozygotes for Pt Metz and a hypoprothrombinemia, have no normal Pt. Purification procedures included barium citrate adsorption and chromatography on DEAE Sephadex as for normal Pt. As opposed to some other variants (Pt Barcelona and Madrid), Pt Metz elutes as a single symetrical peak. By SDS polyacrylamide gel electrophoresis, this material is homogeneous and appears to have the same molecular weight as normal Pt. Comigration of normal and abnormal Pt in the absence of SDS, shows a double band suggesting an abnormal charge for the variant. Pt Metz exhibits an identity reaction with the control by double immunodiffusion. Upon activation by factor Xa, Pt Metz can generate amydolytic activity on Bz-Phe-Val-Arg-pNa (S2160), but only a very low clotting activity. Clear abnormalities are observed in the cleavage pattern of Pt Metz when monitored by SDS gel electrophoresis. The main feature are the accumulation of prethrombin l (Pl) and the appearance of abnormal intermediates migrating faster than Pl.


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