Electrophoretic properties

Solids separation based on density loses its effectiveness as the particle size decreases. For particles below 100 microns, separation methods make use of differences in the magnetic susceptibility (magnetic separation), elec trical conductivity (electrostatic separation), and in the surface wettability (flotation and selec tive flocculation). Treatment of ultrafine solids, say smaller than 10 microns can also be achieved by utilizing differences in dielectric and electrophoretic properties of the particles. 

Electrophoretic properties Isoelectric point, SDS-PAGE profile... 

The conformations of L-adenylyl-(3 5 )-L-adenosine (28) and L-adenylyl-(2 -> 5 )-L-adenosine (29), as deduced from circular dichroic spectra, are different from the corresponding DD-dinucleotides. < The n.m.r. and u.v. absorption spectra of (28) and (29) are the same as the DD-dimers and their chromatographic and electrophoretic properties appear identical. While (28) and (29) are resistant to enzymic hydrolysis they form complexes with polyU. 

H Takenaka, Y Kawashima, SY Lin. Electrophoretic properties of sulfamethoxazole microcapsules and gelatin-acacia coacervates. J Pharm Sci 70 302-305, 1981. 

An interesting twist to the story is provided by studies on N. brasiliensis, which secretes three distinct isoforms of AChE, designated A, B and C (Ogilvie et al, 1973). These enzymes can be easily separated by nondenaturing electrophoresis due to their distinct pis, and this is illustrated in Fig. 11.1, which also shows the distinct electrophoretic properties of the amphiphilic enzyme (arrowed) found only in somatic extracts and therefore presumably associated with neuromuscular function. The overall amount of AChE produced by this parasite increases dramatically following establishment in the jejunum, and a switch in isoform expression occurs,... 

The intracellular localization of carboxylesterases is predominantly microsomal, the esterases being localized in the endoplasmic reticulum [73] [79] [93], They are either free in the lumen or loosely bound to the inner aspect of the membrane. The carboxylesterases in liver mitochondria are essentially identical to those of the microsomal fraction. In contrast, carboxylesterases of liver lysosomes are different, their isoelectric point being in the acidic range. Carboxylesterase activity is also found in the cytosolic fraction of liver and kidney. It has been suggested that cytosolic carboxylesterases are mere contaminants of the microsomal enzymes, but there is evidence that soluble esterases do not necessarily originate from the endoplasmic reticulum [94], In guinea pig liver, a specific cytosolic esterase has been identified that is capable of hydrolyzing acetylsalicylate and that differs from the microsomal enzyme. Also, microsomal and cytosolic enzymes have different electrophoretic properties [77]. Cytosolic and microsomal esterases in rat small intestinal mucosa are clearly different enzymes, since they hydrolyze rac-oxazepam acetate with opposite enantioselectivity [95], Consequently, studies of hydrolysis in hepatocytes reflect more closely the in vivo hepatic hydrolysis than subcellular fractions, since cytosolic and microsomal esterases can act in parallel. 

The fact that for c, no alteration of the electrophoretic properties of the drug was observed leads to the conclusion that the micelle constitution is constant. Any phospholipids or lipids, which form stable and consistent mixed micelles, may be used. 

In liquid chromatography, affinity purification protocols (4-8) have been known for a long time. Naturally, electrophoresis can be used just as well to observe molecular or noncovalent interactions of DNA oligomers, provided the complex has distinct electrophoretic properties different from those of the free molecules. Therefore, affinity capillary electrophoresis (ACE) can be a powerful tool for studying DNA-drug or DNA-biopolymer interactions. Several reviews discussing these aspects of ACE have been published in recent years (9-19). The crucial aspects of DNA in this field are covered comprehensively in a recent overview article (20). 

Figure 3. Gel electrophoretic properties of glandless cottonseed proteins that are soluble at various suspension pH values...

Figure 9. Gel electrophoretic properties of peanut meal proteins that are soluble in suspensions that contain various levels of salt and are at different pH values (25)...

Figure 13. Gel electrophoretic properties of soluble proteins in suspensions at various pH values that contain succinyl-ated liquid cyclone processed cottonseed flour...

In the quantitative sections of this chapter the primary emphasis has been on establishing the relationship between the electrophoretic properties of the system and the zeta potential. We saw in Chapter 11 that potential is a particularly useful quantity for the characterization of lyophobic colloids. In this context, then, the f potential is a valuable property to measure for a lyophobic colloid. For lyophilic colloids such as proteins, on the other hand, the charge of the particle is a more useful way to describe the molecule. In this section we consider briefly what information may be obtained about the charge of a particle from electrophoresis measurements. 

Chen, J., Seeman, N.C. (1991b) The electrophoretic properties of a DNA cube and its sub-structure catenanes. Electrophoresis 12, 607-611 (1991). 

AG Lynch, DM Mulvihill, AJR Law, J Leaver, DS Horne. Chromatographic elution profiles, electrophoretic properties and free amino and sulphydryl group contents of commercial sodium caseinates. Int Dairy J 7 213-220, 1997. 

The CBH I (D) is identical in composition and activity to the CBH I (D) previously described (2) from T. reesei QM 9123. The close correspondence of their amino acid contents (Table VI), the nearly identical content of neutral carbohydrate 6.8% by weight for the CBH I (D) produced in the presence of sophorose and 6.7% for T. reesei QM 9123 CBH I (D) grown on cellulose (2), and identical electrophoretic properties clearly argue for a common molecular structure for these CBH s I (D). The CBH II is clearly different from all other CBH s in electrophoretic mobility (Figure 12) and amino acid composition (41), but is devoid of endoglucanase activity and produces predominantly cellobiose (>90% by weight of soluble products) from cellulose. It has a sedimentation coefficient of 3.71 in comparison to CBH I (D), for which a value of 3.66 was obtained. 

Proteins are complex molecules, and classification has been based mostly on solubility in different solvents. Increasingly, however, as more knowledge about molecular composition and structure is obtained, other criteria are being used for classification. These include behavior in the ultracentrifuge and electrophoretic properties. Proteins are divided into the following main groups simple, conjugated, and derived proteins. 

McWatters and Cherry (9) characterized the emulsion and foam capacity, emulsion viscosity, protein solubility, and gel electrophoretic properties of water suspensions containing... 

Figure 8. Gel electrophoretic properties of peanut proteins as influenced by pH...

Figure 14. Gel electrophoretic properties of proteins in peanut flour treated with...

Solubility of Exocellular Nickel Complexes in Soil. To identify those complexes most important in mobilizing Ni in soil, the filtrates (<0.01) of the exocellular media from 20 representative bacterial cultures and all fungal cultures were passed through a column of the soil from which the organisms were isolated and the solubility, and chromatographic and electrophoretic properties of Ni in sterile water, sterile medium and exocellular medium were compared before and after elution through soil. 

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