2-Mercaptoethanol density

Fig. 12. Diagram of elution pattern of red cell acid phosphatase and various markers on Biogel P 60. The position of the various protein markers was determined both by optical density determination and by starch gel electrophoresis of the individual fractions (83). The experiment was carried out using a polyacrylamide gel (Biogel P 60, 50-150 mesh exclusion limit >60,000 Bio-Rad Laboratories, California) in 0.05 M tris buffer, pH 8.0, containing 0.08% (v/v) Tween 80 and 0.1% (v/v) 2-mercaptoethanol to stabilize the enzyme. Column 60 X 4 cm. Flow rate 20 ml/hr, 4 ml fractions. (A) OD at 280 nm, ( ) OD at 540 nm, ( ) LDH assay with p-nitrophenyl phosphate for AcP. From Hopkinson and Harris (85).

Just as the auto mechanic sometimes has parts left over, electron-density maps occasionally show clear, empty density after all known contents of the crystal have been located. Apparent density can appear as an artifact of missing Fourier terms, but this density disappears when a more complete set of data is obtained. Among the possible explanations for density that is not artifactual are ions like phosphate and sulfate from the mother liquor reagents like mercaptoethanol, dithiothreitol, or detergents used in purification or crystallization or cofactors, inhibitors, allosteric effectors, or other small molecules that survived the protein purification. Later discovery of previously unknown but important ligands has sometimes resulted in subsequent interpretation of empty density. 

Purify the lipase by affinity chromatography on heparin-Sepharose Ki 0.026mM for very low density lipoprotein. It is inhibited by 2-mercaptoethanol, Cys, Ca, Hg, Mg and Mn ions. Protamine sulfate, Img of bovine serum albumin/mL or in 50% glycerol at -70 , stabilises the lipase for several days. 60% loss of activity occurs at 0°/lhour in the presence of 1% of bovine serum albumin. [Shirai et al. Biochim Biophys Acta 665 504 7957.]... 

MDPE. See Polyethylene, medium density 2-ME. See2-Mercaptoethanol Methoxyethanol MEA. See Ethanolamine 2-MEA. See Methoxyethanol acetate... 

Patron and Moretti [255] also reported the bulk polymerization of vinyl chloride at >0°C in the presence of a catalyst system consisting of an organic hydroperoxide, SO2, and an alcohol or metal al(X)holate. A 25% conversion was obtained at 25°C. The PVC recovered had an intrinsic viscosity of 1.3 and bulk density of 0.41 g cm . They [260] also reported the bulk polymerization of vinyl chloride by taking a mixture containing liquid vinyl chloride at — 30°C and a catalyst composition containing cumene hydroperoxide, SO2, Na methylate, and 2-mercaptoethanol that was continuously fed to a reactor. The molar weight concentration ratio of the catalyst composition... 

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