Electrophoresis molecular weight determination

DNA is subsequently analyzed by various characterization techniques, such as molecular weight determination, electrophoresis, and hybridization to known probes. Using these methods, the presence of DNA unique to a particular species can be confirmed. Alternatively, with appropriate primers, a mixture of DNA fragments, which are uniquely characteristic of an individual or organism, will result in a fingerprint that can be used for identification. 

Molecular weight determination The molecular weight of the purified enzyme was determined by both gel filtration chromatograph and SDS polyacrylamide gel electrophoresis (16). Toyopearl 55HW gel (Toyo SF 160K, Toyo, Co.,Ltd., Tokyo) was used for gel filtration and 0.05 N acetate buffer pH 5.25 was used as buffer. 

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. 

Weber, K. and Osborn, M. 1969. The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. J. Biol Chem. 244, 4406-4412. 

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. 

This form of electrophoresis is not directly applicable to molecular weight determinations of glycoproteins. Glycoproteins and glycopeptides containing more than 10% carbohydrate behave... 

J.P. Segrest and R.L. Jackson, Molecular weight determination of glycoproteins by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, in V. Ginsburg (Ed.), Methods in Enzymology, Vol. XXVIII, Complex Carbohydrates, Part B, Academic Press, New York, 1972, pp. 54-63. 

Be familiar with methods for protein molecular weight determination and the limitations of such methods gel filtration, gel electrophoresis, and hydrodynamic methods. 

Another widely used procedure for molecular weight determinations is gel electrophoresis, in which the migration of proteins is accomplished through an electrical field. To avoid shape effects on the rate of migration, as well as differences in net charge, most proteins may be rendered into a random coil con-... 

Dynamic sieving capillary electrophoresis (DSCE) employs a polymer solution as the sieving agent. It is introduced into the capillary under pressure and replenished after each analysis. The UV transparency of polymer solutions enables determination of native proteins. DSCE can be used for molecular weight determination of SDS-protein complexes because they migrate proportional to their molecular size. Polymer systems have been developed that provide good resolution of proteins in the 14-200 kDA range. 

K. Weber and M. Osborn, J. Biol. Chem., 244 4406-4412 (1969). The Reliability of Molecular Weight Determinations by Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis. 

Capillary gel electrophoresis (CGE), Size determination Protein molecular weight determination, aggregates, oligonucleotides, DNA fragments, polysaccharides... 

Capillary isoelectric focusing coupled to mass spectrometry has gained popularity in recent years (by analogy to two-dimensional gel electrophoresis). Additional information obtained from mass spectrometry includes not only precise molecular-weight determination but also the possiblity for peptide sequencing. Analysis of hemoglobin variants, recombinant proteins, and monoclonal antibodies have been demonstrated [1,7,8]. 

---