Corn, electrophoresis

FIG. 4 SDS gel electrophoresis of insoluble gluten samples from laboratory corn wet milling. Lane 1 Molecular mass standards (250, 150, 100, 75, 50, 37, 25, 15, and lOkDa). Lane 2 Enzymatic milling with commercial protease with added S02 and lactic acid. Lane 3 Enzymatic milling with commercial protease and no added S02. Lane 4 Conventional laboratory milling. Lane 5 Enzymatic milling using Bromelain and no added S02. 

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. 

A very exciting development in multidimensional separation involves the coupling of LC to GC or other techniques, such as capillary electrophoresis (CE). Online coupling of LC with multidimensional GC has allowed efficient determination of the stilbene hormones in corned beef (3), whereas LC-GC coupling permitted determination of levamisole residues in milk (4). With these hyphenated techniques, the potential of selective separation is becoming increasingly apparent. 

C. C. Chery, H. Chassaigne, L. Verbeeck, R. Cornelis, F. Vanhaecke, L. Moens, Detection and quantiPcation of selenium in proteins by means of gel electrophoresis and electrothermal vaporization ICP-MS, J. Anal. Atom. Spectrom., 17 (2002), 576D580. 

Fig. 5A-C. Rapid changes in protein phosphorylation in roots of Merit corn. Apical segments of dark-grown roots were preloaded with for 1 h, then washed in buffer. A Dark controls were left in buffer for 15 min B for light treatment, roots were exposed to light for 7 min after 8 min dark incubation C light treatment was the same as in B. but EGTA-I-A23187 was present for 15 min. Proteins were extracted and separated by two-dimensional gel electrophoresis as described earlier [45]. Arrows indicate the phosphoproteins that are affected by light [27]...

Dextrins obtained on y-irradiation of starch have been found to contain appreciable proportions of unidentified carbonyl residues. The properties of starch for starch-gel electrophoresis were improved by y-irradiation. The decreases in viscosity and iodine-absorption values, as well as the increased reducing properties, indicated that amylose and amylopectin are degraded by y-irradiation in the same way as native starches. Although each of the amylose and amylopectin components of amylomaize starch in y-irradiated and untreated samples was hydrolysed by a-amylase to the same extent, y-irradiated amylose had a low p-amylolysis limit. /-Irradiated amylomaize and com starches were hydrolysed to greater extents by a-amylase as the radiation dose was increased, and differences were detected in the products of enzymic degradation of amylomaize and corn starches following y-radiolysis. The water-soluble dextrins formed on y-irradiation of maize starch have been examined. ... 

In Table 2, the values of n are presented for the intact membrane, solubilized membrane, reaggregated material and Triton X-100 solubilized reaggregated material from animals fed corn oil supplemented diet and fat-free diet, respectively. As it can be observed, the value of n is around 1.6 for all the enzyme preparations from the fat sufficient animals. For the preparations from the fat deficient animals instead it is in the order of 1.0 in the case of intact membrane and reaggregation membrane like material, and around 1.6 for the solubilized preparations. Similar results were obtained with the other solubilizing agents (Martinez de Melian et al., 1976). Further evidence on the role played by the membrane was obtained when the acetylcholinesterase band from the gel electrophoresis of solubilized acetylcholinesterase from fat sufficient animals was eluted, mixed with lipid extracted from red cell membranes of rat fed a fat-free diet, and diffused against buffer. A value of n=1.0, which corresponds to that of the intact membrane from the deficient... 

Malate Enzyme. Malate enzyme, as well as the other enzymes of the pathway, is known to exist in multiple forms. In apple fruit, Dilley (1966) isolated and purified a form which ran as a single band on acrylamide gels. In corn root tissue, we were able to locate a single isoenzyme (by starch gel electrophoresis) and reported evidence that it was a soluble or nonparticulate protein (Danner and Ting, 1967). Hence, it was concluded that dark CO2 metabolism, insofar as it is mediated by this particular malate enzyme isoenzyme, is in the cytosol. 

Cyclodextrin n-Glucanotransferase.—Cyclodextrin D-glucanotransferase has been prepared from culture fluids of a Bacillus species by adsorption onto corn starch, fractional precipitation with ammonium sulphate, ion-exchange chromatography, and gel filtration. Disc electrophoresis and isoelectric focusing separated the enzyme into two fractions (p7 6.07 and 6.80), which were able to synthesize cycloamyloses (predominantly cyclohepta-amylose) from starch. The enzymes differ from the cyclodextrin o-glucanotransferase from B. macerans, notably in their actions on starch. 

Figure 4. Suppression of DNA fragmentation caused by Trp-P-1 in P-NF-treated rat hepatocytes. Hepatocytes were isolated from P-naphthoflavone (P-NF) and corn oil (C)-treated rats and cultured for 20 h. These hepatocytes were treated with Trp-P-1 for 6 h, and DNA fragmentation was analyzed by 2% agarose gel electrophoresis.

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