Molecular-weight determination by gel

The highest degree of purification was achieved with extracellular endopectate lyase from the anaerobic bacterium Clostridium fel-sineum.Mi A 225-fold purified preparation, homogeneous in disc electrophoresis, was obtained by precipitation with ethanol, and chromatography on CM-cellulose and on Sephadex G-200. Its molecular weight (determined by gel chromatography) was 105,000. 

Molecular weight determined by gel electrophoresis experiments. bEP data for type III sites is subject to error. 

Polypeptide Chain Molecular Weight Determination by Gel Permeation Studies on Agarose Columns in 6M Guanidinium Chloride... 

The molecular weights determined by gel permeation analysis in high osmolarity (155 mM), agree with the particle weights obtained by SDS gel electrophoresis or sed-mentation equilibrium in the ultracentrifuge. The ability to transform to a less compact orm in low osmolarity (5 mM) appears to be a common property of all mutarotases. 

MPO from H. niger was isolated and its molecular weight determined by gel filtration (135 kDa) and the SDS-PAGE analysis showed that the enzyme is a dimmer [140]. MPO has also been obtained from other plant speeies such as D. stramonium [141] and N. tabacum [142], Inhibition studies of Hyoscyamus MPO demonstrated the quinoprotein characteristic of this enzyme [140], a feature previously reported for N. tabacum MPO, after conducting a suicidal inhibition of the enzyme with phenyUiydrazine [143]. 

Mass spectrometry can determine the molecular weights of peptides and proteins with mass accuracies orders of magnitude better than the molecular weights determined by gel electrophoresis. It is important to note that in determining molecular... 

A deoxyadenosylcobalamin-dependent ribonucleoside triphosphate reductase has been partially purified from cell free extracts of the extreme thermophile, Thermus X-l 14). The enzyme preparation catalyzed the reduction of GTP and CTP at comparable rates, while UTP and ATP were reduced at only one-tenth the rate of GTP reduction. Only the dithiols could serve as reducing substrates. The enzyme has a temperature optimum of 70°, and the allosteric regulation of the enzyme activity is also temperature-dependent. The reduction of ATP is specifically stimulated by dGTP only at a higher temperature. Maximum stimulation of ATP reduction is observed at approximately 75°, while no stimulation can be detected at 37°. The molecular weight determined by gel filtration was approximately 80,000 but no information about the subunit structure is yet available. 

The dextran used in this work was the commercially available Dextran T-40 (Farmacia), produced by Leuconostoc mesenteroides B512 species. The average molecular weight determined by gel permeation chromatography was = 13,000, = 36,000. Dex-... 

A j8-D-2-acetamido-2-deoxyglucosidase from E. coli has been purified to near homogeneity by electrophoresis on polyacrylamide gel in the presence of sodium dodecyl sulphate and urea. Studies of the substrate specificity of the purified enzyme (pH optimum 7.7, Km (for 4-nitrophenyl 2-acetamido-2-deoxy-l3-D-gluco-pyranoside 0.43 mmol 1 ) confirmed that it has an exo-action. The molecular weight (determined by gel filtration and by gel electrophoresis) of the enzyme in a dissociating medium is 2.6 x 10, showing that it does not contain subunits. 

Spatorico, A.L. and Coulter, B. (1973) Molecular-weight determinations by gel-permeation chromatography and viscometry. Journal of Polymer Science Part B-Polymer Physics, 11,1139-1150. 

Solubility tests carried out on the polymers revealed that all the LC poly (azomethine esters) were insoluble in common organic solvents such as chloroform, THF and acetone. This leads to the difficulty in their molecular weight determination by gel permeation chromatography (GPC). The inherent viscosities (r ii ) of the polymers 3 (a-d) were as given in Table 12.1. The low inherent viscosities may be attributed to the poor solubility of the polymers in the polymerization solution. Precipitate was also formed during the polymerization which hinders further propagation of the polymer chain and thus leads to lower molecular weight. 

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