Molecular composition electrophoresis

Spegel, P., L. Schweitz, et al. (2001). Molecularly imprinted microparticles for capillary electrochromatography studies on microparticle synthesis and electrolyte composition. Electrophoresis 22(17) 3833-3841. 

Due to the insolubility of AP-aggregates, fibril formation could not be analyzed directly by mass spectrometry. In order to determine the molecular composition of aggregates, in gel tryptic digestion and mass spectrometric analysis of the gel electrophoresis bands of Ap-oligomers was performed. AP(l-40) was subjected to fibril growth at 1 J,g/ jL (220 pM) in buffer solution, pH 7.5, and incubated for 5 days at... 

Polyacrylamide gel electrophoresis is one of the most commonly used electrophoretic methods. AnalyMcal uses of this technique center around protein characterization, for example, purity, size, or molecular weight, and composition of a protein. Polyacrylamide gels can be used in both reduced and nonreduced systems as weU as in combination with discontinuous and ief systems (39). 

Most of the applications of HPLC for protein analysis deal with the storage proteins in cereals (wheat, corn, rice, oat, barley) and beans (pea, soybeans). HPLC has proved useful for cultivar identihcation, protein separation, and characterization to detect adulterations (illegal addition of common wheat flour to durum wheat flour) [107]. Recently Losso et al. [146] have reported a rapid method for rice prolamin separation by perfusion chromatography on a RP POROS RH/2 column (UV detection at 230nm), sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), and molecular size determination by MALDl-MS. DuPont et al. [147] used a combination of RP-HPLC and SDS-PAGE to determine the composition of wheat flour proteins previously fractionated by sequential extraction. 

Garcfa-Carreno, EL. 1993. Substrate-gel electrophoresis for composition and molecular weight of proteinases or proteinaceous proteinase inhibitor. Anal. Biochem. 214 65-69. 

Although apoB-100 is virtually the sole form of apoB in VLDL, many speciments of LDL also contain two additional forms of apoB which Kane et al. have called B-74 and B-26 (as their mobility on SDS-polyacrylamide gel electrophoresis suggests proteins of apparent molecular weight 74% and 26% of B-100 (K4). Kane et al. suggest that the B-74 and B-26 forms are fragments of the original B-100 form. As evidence they note that equimolar amounts of B-74 and B-26 are found in LDL samples, and that while the amino acid compositions of B-74 and B-26 difler from each other and from B-100, the calculated amino acid composition of an equimolar mixture of B-74 and B-26 is similar or identical to that of B-100 (H8). 

Subunit Composition of a Protein A protein has a molecular mass of 400 kDa when measured by gel filtration. When subjected to gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), the protein gives three bands with molecular masses of 180, 160, and 60 kDa. When electrophoresis is carried out in the presence of SDS and dithiothreitol, three bands are again formed, this time with molecular masses of 160, 90, and 60 kDa. Determine the subunit composition of the protein. 

The brain enzyme has been purified over 1000-fold and shown to be homogeneous by ultracentrifugation and electrophoresis criteria (36) the activity ratio for acetyl-P over carbamyl-P remains unchanged with purification. This enzyme is one of the smallest on record the molecular weight from physical data is 13,200 and from amino acid analysis is 12,600 the amino acid composition of the enzyme is given in Table I. The terminal amino acid is aspartic acid (25). Cystine has not been detected. 

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