Molecular weight standards

Fig. 3. Sodium dodecyl sulfate—polyacrylamide gel electrophoretic pattern for molecular weight standards (lane 1) water-extractable proteins of defatted soybean meal (lane 2) purified IIS (glycinin) (lane 3) and purified 7S (P-conglycinin) (lane 4) where the numbers represent mol wt x 10. The gel was mn in the presence of 2-mercaptoethanol, resulting in the cleavage of the disulfide bond linking the acidic (A bands) and basic (B bands) polypeptides of the...

Calibrate the system. Use narrowly dispersed molecular weight standards of the polymer of interest to construct a calibration curve of log molecular weight versus elution volume (Eig. 3.2). If a more sophisticated software system is available, a broad molecular weight standard may be used to calibrate the system. 

Description Particle size (/tm) Minimum theoreticai piates/30 cm Exclusion limit (polystyrene molecular weight) Standard flow rate (ml/min) Maximum flow rate (ml/min) Maximum pressure drop/30 cm (bar)... 

Figure 6.21 shows the calibration curves of the SB-800 HQ series using standard pullulan. Because a high molecular weight standard sample is not available, the calibration curves of 805 and 806 are partly estimates (dotted lines). The difference in the conformation between polyethylene oxide (PEO) and pullulan in the solvent causes a shift of the calibration curves of pullulan slightly higher than those of PEO. The OHpak SB-800HQ series is better suited for the analysis of hydrophilic samples than the Asahipak GS/GE series. 

Measurement by gel permeation chromatography in 0.2 M phosphate buffer pH 7.0 with polystyrenesulfate or polyethylene glycols ([5] in the case of aureobasidium sp. A-91) as molecular weight standards. Data processing as de.scribed in Ref. [II]. 

Anionic pol5Tnerizations make the molecular weight standards that are used to calibrate size-exclusion chromatographs. Equation (13.38) predicts PD = 1.001 at In = 1000. Actual measurements give about 1.05. The difference is attributed to impurities in the feed that cause terminations and thus short chains. Also, the chromatograph has internal dispersion so that a truly monodisperse sample would show some spread. Even so, a PD of E05 is extremely narrow by pol5Tner standards. This does not mean it is narrow in an... 

At the moment, one recommends to determine the molecular characteristics of pectins using SEC chromatography equipped with a differential refractometer, a multiangle laser light scattering detector and a viscometer as previously described [25]. This technique needs no calibration with the usual molecular weight standards such dextrans and pullulans... 

Figure 1. a - SDS-PAGE of fraction T (silver staining), lane 1 fraction T, lane 2 ovalbumine and lane 3 molecular weight standards. 

Figure 4. Purification of PemB from E. coli K38 pGPl-2/pPME6-5 cells. Proteins were separated by urea-SDS-PAGE. Lane 1, induced cell lysate lane 2, soluble protein fraction from induced cells lane 3, membrane fraction from non-induced cells lane 4, membrane fraction from induced cells lane 5, membrane proteins not extracted by Triton X-100 lane 6, membrane proteins extracted by Triton X-100 lane 7, PemB purified by preparative electrophoresis. The molecular weight standard positions are indicated.

V. Copolvmerization Kinetics. Qassical copolymerization kinetics commonly provides equations for instantaneous property distributions (e.g. sequence length) and sometimes for accumulated instantaneous (i.e. for high conversion samples) as well (e.g. copolymer composition). These can serve as the basis upon whkh to derive nations which would reflect detector response for a GPC separation based upon properties other than molecular weight. The distributions can then serve as c bration standards analagous to the use of molecular weight standards. 

Herein are reported improved methods of molecular weight calibration where simultaneously, peak broadening parameters (a) are obtained through the use of multiple polydisperse molecular weight standards. There are two basic methods covered. The first and most reliable method employs the universal molecular weight calibration curve obtained using narrow MWD polystyrene standards. 

Della-Penna, D., Christofferson, R.E., and Bennett, A.B. (1986) Biotinylated proteins as molecular weight standards on Western blots. Anal. Biochem. 152, 329-332. 

FIGURE 4 Effect of sample preparation on the fragmentation of an rMAb observed in (A) SDS-PAGE and (B) CE-SDS with LIF detection. SDS-PAGE lanes (Lane I) molecular weight standards bovine serum albumin at (Lane 2) 8 ng and (Lane 3) 2 ng (Lane 4) rMAb control after alkylation with (Lane 5) iodoacetic acid and (Lane 6) iodoacetamide. (See color plate 4.)... 

Figure 3 Biosynthesis and purification of 90-kD elastin analogue analyzed by denaturing polyacrylamide gel electrophoresis (10-15% gradient, visualized by silver staining). Lanes 1-7 time course of target protein expression at 0, 30, 60, 90, 120, 150, and 180 minutes after induction. Lane 9 soluble lysate of induced E. coli expression strain BLR(DE3)pRAMl. Lanes 10-13 protein fractions obtained from immobilized metal affinity chromatography of the lysate on nickel-NTA agarose (imidazole gradient elution). Lanes 8,14 protein molecular weight standards of 50, 75, 100, and 150 kD.

Figure 6. 10-15% SDS polyacrylamide gel of lane 1 — untreated E, coli extract (0 mM KCl) lane 2 — the peak GUS fraction from the HPLC separation of untreated extract lane 3 — Sigma SDS-7 molecular weight standards (approximate molecular weights of 4 standards are indicated on the right hand edge of the figure) lane 4 — BPA-1000 treated E. coli extract (4000 ppm BPA-1000 and 300 mM KCl) lane 5 — the peak GUS fraction from the HPLC separation of BPA-1000 treated extract. GUS migrates slightly slower than the 66,000 molecular weight standard.

DTT-dependent and -independent RNAse inhibitors (Ambion), NTPs, dNTPs, MgClj, MnCl, yeast t-RNA, DNA, and RNA molecular weight standards. 

The sample fluid could be any neat liquid or a sample of polymer solution. Under favorable conditions, a single viscosity determination on a polymer solution at high dilution can provide a direct measure of the polymer intrinsic viscosity, without the need of polymer concentration extrapolation. With this viscometer used as a continuous viscosity detector for SEC, it is possible to achieve SEC molecluar weight calibration by way of the universal SEC calibration methodology without the need of molecular weight standards for the unknown polymers. 

Fig. 2.2.4.1 SDS-PAGE analysis of recombinant LK-ADH purification. Lane 1 molecular weight standards (kDa) Lane 2 crude extract of recombinant . coli BL21(DE3)/pADH Lane 3 ADH after anion-exchange chromatography.

Fig. 18.5 Poly(styrene) high molecular weight standards.

Materials and Solution Preparation. The poly( 1-amidoethylene) used in all experiments was a molecular weight standard supplied by Polysciences, Inc., as material 8249, batch 93-5. The polymer was dried for 3 hr. under a vacuum of < 10 Pa at a temperature of 25°C. The polymer was dispersed on a vortex of 0.01 M Na2S04 solution and stirred for 1 day. The solution was then centrifuged to remove undissolved polymer particles and the preweighed centrifuge tube was dried and reweighed. The polymer concentration of the master sample was calculated from the weight of polymer retained in the solution. The concentration of the master sample was 2,115 ppm or 0.2115 g/dL. 

The polystyrene (PS) and polymethylmethacrylate (PMMA) narrow molecular weight standards were obtained from three kits (Polymer Laboratories, S-L-10, S-M-10 and M-M-10) covering the range from 3,000,000 to 500. Five nonylphenyl-terminated polyethylene oxides (Aldrich, Igepals)... 

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