Dextran, activation

Myeloma proteins occur in animal tumors of various types. The synthesis of these proteins can be induced in some experimental animals by injection of mineral oil, or the implantation of plastic discs.161 Myeloma proteins were shown to possess antibody activity, with specificity for different types of substances.161 Some of these proteins were found to combine with such carbohydrates as bacterial, cell-wall polysaccharides, lipopolysaccharides, dextrans, levans, and galactans.162 Myeloma proteins that combine with galactans or dextrans possess anti-galactan activity,163,164 or anti-dextran activity,165-167 and have been studied most extensively. 

Weigert and coworkers compared the idiotypes of three immunoglobulins having anti-(l — 3)-a-dextran activity,63 namely, IgA s UPC 102, J 558, and IgM MOPC 104E. Both MOPC 104E and UPC 102 could completely inhibit the 125I-labeled J 558-anti-J 558... 

Soluble polysaccharides (dextrans) activated with cyanogen bromide have been attached to enzymes in order to prepare neoglycoproteins.7 The conditions for activating the soluble polysaccharides are some-... 

Fig. 48 Introduction of aldehyde functions by conversion of 3-chloro-2-hydroxypropyl dextran (activated dextran) with hydroxybenzaldehyde A or carboxybenzaldehyde (A, lower part, B)...

Figure 3. Degree of derivatization of dextran activation with CDI...

In the same investigation (55) it was found that an IgM myeloma protein with Xo chains and anti-a(l — 3)dextran activity had all the idiotypic determinants of an IgA (Xo) protein with the same activity, but that relatively high concentrations of the IgM protein were required to inhibit binding of the IgA protein to its antiidiotypic antibodies. This result suggested that the Vh regions of the proteins may be similar but not identical. 

Active immobilized enzyme possessing haemagglutinating activity Active immobilized enzyme kinetic studies and the hydrolysis of dextrans Active immobilized enzyme for a continuous fluidized-bed reactor... 

Polarimetric determination of the sucrose concentration of a solution is vaUd when sucrose is the only optically active constituent of the sample. In practice, sugar solutions are almost never pure, but contain other optically active substances, most notably the products of sucrose inversion, fmctose and glucose, and sometimes also the microbial polysaccharide dextran, which is dextrorotatory. Corrections can be made for the presence of impurities, such as invert, moisture, and ash. The advantage of polarization is that it is rapid, easy, and very reproducible, having a precision of 0.001°. 

The main problem of determination of molecular weight distribution (MWD) of dextrans (polysachaiides which ai e used as active substances for infusion medicines) is low robustness of the existing method. It means that obtained results are strongly dependent on controlled and uncontrolled pai ameters of chromatographic system standai d substances for calibration loading on columns etc. It has been shoved on practical examples. 

Other important examples are blood and blood products, which are collected and processed in sterile containers, and plasma substitutes, for example dextrans and degraded gelatin. Dextrans, glucose polymers consisting essentially of (1 - 6) a-links, are produced as a result of the biochemical activities of certain bacteria of the genus Leuconostoc, e.g. L. mesenteroides (see Chapter 25). 

Gel Filtration. The lyophilized protein was redissolved in 50 mM phosphate buffer, pH 7.4 0.15 m NaCl 0.013 % sodium azide and loaded on a Superdex 75HR1030 column equilibrated with the same buffer. Elution was downward flow (0.15 ml/min) and 0.25 ml fi actions were collected. Fractions with pectin lyase activity were combined, dialyzed against distilled water and used in the next step. To estimate the molecular mass of PNL, the column was calibrated with standard proteins (Sigma MW-GF-70 Albumin, 66,000 Da Carbonic Anhidrase, 29,00 Cytochrome, 12,400 and Aprotinin, 6,500). The proteins were eluted in the conditions described above and their volumes (F ) were calculated fi om the peak maximum of the absorbance at 280 nm. The partition coefficient was obtained fi om the relationship where F, represents the bed volmne of column and F the void volume (which was calculated using blue dextran. Sigma). The molecular mass was determined using a standard curve of vs the logarithm of the molecular masses of the standards [28, 29]... 

PGIP, purified fi om P.vulgaris hypocotyls [11], was immobilized to the sensor ch via amine coupling. A continuous flow of HBS buffer (5 pl/min) was mantained over the sensor surface. The carboxylated dextran matrix of the sensor surface was first activated by a 6-min injection of a mixture of N-hydroxy-succinimide and N-ethyl-N - (3-diethylaminopropyl) carbodiimide, followed by a 7-min injection of PGIP (lOng/pl in 10 mM acetate, pH 5.0). Hie immobilization procedure was con leted by a 7-min injection of 1 M ethanolamine hydrochloride to block the remaining ester groups. 

Molecular weight of the components of the enzymatic complex was determined using a Sephadex G —75 column after its calibration by dextrans with molecular weight equal to 10,000, 40,000 and 70,000 and rafinose with molecular weight of 504. Fractions were also analyzed by the disk —electrophoresis method in PAAG (7) using 7.5% polyacrilamide gel (pH 4.3). Activity of pectinesterase was determined by titrometric method [8]. The enzymatically released methanol analyzed by gas—liquid chromatography [9]. 

Chemically dextrans are similar to one another. The activation energy for acid hydrolysis is about 30-35 Kcal/mol (5j. The C-2 hydroxyls appear to be the most reactive in most Lewis base and acid-type reactions. A wide variety of esters and ethers have been described as well as carbonates and xanthates ( 7,8j. In alkaline solution, dextran forms a varying complex with a number of metal ions (9). 

Figure 4 Anti-angiogenic activity of 1 and 3. (A) Angiographic images of the developmental CAM (EDD 9) treated with 0.9% NaCl (control) and 1 and 3 (150 pM/day). The vasculature is visualized by FITC-dextran fluorescence angiography (25 mg/kg, 20 kDa, XCK = 470 nm, Xem = 520 nm).

Morimoto et al. [33] demonstrated that the ocular absorption of hydrophilic compounds over a wide range of molecular weights could be increased by 2 and 10 mM sodium taurocholate and sodium taurodeoxycholate in a dose-dependent manner. The compounds were glutathione (307 Da), 6-carboxyfluorescein (376 Da), FTTC-dextran (4 kDa), and insulin (5.7 kDa). Of the two bile salts, sodium taurodeoxycholate was more effective. At 10 mM, this bile salt increased the permeability of 6-carboxyfluorescein from 0.02% to 11%, glutathione from 0.08% to 6%, FITC-dextran from 0% to 0.07%, and insulin from 0.06% to 3.8%. Sodium taurocholate, on the other hand, increased the permeability to 0.13%, 0.38%, 0.0011%, and 0.14%, respectively. Taurodeoxycholate was more effective than taurocholate in the nasal epithelium as well [202], This difference in activities can possibly be attributed to their micelle-forming capability, which is higher for taurodeoxycholate, a dihydroxy bile salt [190],... 

Dextrans are also attractive as macromolecular carriers of paramagnetic chelates because of their hydrophilicity, the different available molecular weights with narrow polydispersity, and the versatility of activation methods applicable. Several DTPA- or DOTA-loaded carboxymethyl dextran (CMD) derivatives have been prepared and tested in blood pool MRI.136-139 The relaxivities reported for these compounds are, however, relatively moderate. 

Tarr and Hibbert27 determined the optimal conditions for the preparation of dextran. Sucrose was found to be the only suitable carbohydrate substrate, although some strains produced a small amount of dextran from D-glucose. The formation of dextran from D-glucose had been observed occasionally by earlier workers, but such formation is of somewhat transient character, occurring only when the cultures are very active with respect to the formation of polysaccharides from sucrose.27 The nutrient solution (pH 8.0) used by Tarr and Hibbert27 for dextran... 

Dextran is probably identical with the capsular carbohydrate of Leuconoatoc, but capsules3 have not always been observed, even with Leuconoatoc organisms which actively produced dextran.27,32... 

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