Maltoside preparation

Hydroxyjuglone glucosides and maltosides, prepared by an ortho-ester procedure, have been found to be more effective antifungal agents than the parent aglycone. ... 

Attempts66 to prepare the 2,3-anhydride from methyl 3-0-(methyl-sulfonyl)-/3-maltoside, using M sodium methoxide, resulted in the corresponding 3,6-anhydride 43. To circumvent the formation of 43, the reaction was performed with methyl 3-0-(methylsulfonyl)-6,6 -di-0-trityl-/3-maltoside. The desired product, methyl 2,3-anhydro-4-0-(2,3,4-tri-0-acetyl-6-0-trityl-a-D-glucopyranosyl)-6-0-trityl-/3-D-allopyrano-side (44), was obtained in 72% yield. Attempted detritylation of 44 by brief treatment with hydrogen bromide in glacial acetic acid, followed by conventional acetylation, gave methyl 2,6,2, 3, 4, 6 -hexa-0-acetyl-... 

The observed differences [3] in the reactivity of primary hydroxyl groups were preparatively exploited in the structural modifications of oligosaccharides. The monomolar tritylation of phenyl a-maltoside gives the 6 - to 6- ratio of about 1.3, whereas 2.9 is observed for phenyl P-maltoside [269]. Generally, the orientation of... 

The PSI-200 preparation can be subjected to further fractionation by solubilisation in the detergent dodecyl maltoside, followed by sucrose gradient ultracentrifugation (Bassi and Simpson 1987c). This... 

The immobilization of trimeric LHCII is demonstrated in Fig. 13(B). After the nickel ion activation (5), a 1 pM solution of trimeric recombinant LHCII prepared in NaP + DM buffer (20 mM sodium phosphate, pH 7.4, 0.1 % (w/v) n-dodecyl-/ -D-maltoside) was introduced into the flow cell (1). For each cycle, the protein solution was incubated in the loop for 30 min, followed by buffer rinse (2), EDTA (3), and SDS (4) regeneration. EDTA was used to competitively chelate the nickel ions and break the linkage between NTA and Histidine. SDS, as mentioned in Section 4.2, was used to detach any remaining physically adsorbed proteins. As shown in Fig. 13(B), the immobilization/regeneration cycles from (1) to (5) can be well reproduced and the baseline after every cycle stabilized at a response close to the starting level. This indicates that the... 

Orthorhombic crystals obtained from the preparations stabilized with the detergent decyl maltoside diffracted X-rays up to a maximum resolution of 2.3 resolution from non-frozen crystals (Yoshikawa et ah, 1998). No commercially available detergent other than decyl maltoside has been found that will produce orthorhombic crystals. Even dodecyl maltoside, only two alkyl chain units longer than decyl maltoside, did not produce crystals even though the detergent stabilizes the enzyme effectively. It should... 

Selective sulfonylation of primary hydroxyl groups has also been demonstrated in oligosaccharides and polysaccharides. Thus, Ume-zawa and coworkers used sequential p-toluenesulfonylation and acetylation to obtain crystalline l,2,2, 3,3, 4 -hexa-0-acetyl-6,6 -di-0-p-tolylsulfonyl-/8-maltose in 45% yield. From methyl /3-maltoside, Wolfrom and coworkers prepared crystalline methyl 6,6 -di-0-p-tolylsulfonyl- -maltoside in 86% yield. Crystalline derivatives have... 

Vineland, NJ) or over-the-counter cosmetic creams promoted for improved hydration (L Oreal, Paris and Dior, Paris). More recently, parenteral liposome formulations of amphotericin B, doxorubicin, and dau-norubicin have been approved and marketed (ABELCET, Elan, the Liposome Co., Inc, Princeton, NJ AmBisome and DaunoXome, Nexstar/Fujisawa, Deerfield Park, IL Amphotec and Doxil, Sequus/ Alza, Menlo Park, CA), with others on the horizon for applications in photodynamic therapy. Although the vast majority of liposome preparations are constructed from phospholipids, other nonphospholipid materials can be used either alone or in mixtures to form bilayer arrays. One such example is Amphotec, which utilizes sodium cholesteryl sulfate as the primary lipid. Other liposome forming materials may include but are not limited to fatty-acid compositions, ionized fatty acids, or fatty acyl amino acids, longchain fatty alcohols plus surfactants, ionized lysophospholipids or combinations, non-ionic or ionic surfactants and amphiphiles, alkyl maltosides, a-tocopherol esters, cholesterol esters, polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polymerized phospholipid compositions. ° ... 

Maltoside analogs with 5-thioglucose at the nonreducing end and the corresponding k-thioglycosides were prepared as potential glycosidase inhibitors by the same group [79,80]. 

Carbohydrate crown ethers were obtained with ethylene spacers from a crown ether point of view, the carbohydrate vicinal diols are replacing one ethylene glycol unit [181,182], Cyclic compounds synthesized include bis-gluco-15-crown-5 82, bis-gluco-21-crown-7, and tetra-gluco-24-crown-8 (O Scheme 14). These chiral macrocycles could serve as catalysts in the asymmetric Michael addition of methyl a-phenylacetate to methyl acrylate. With the goal to study molecular interactions, P,P, and Q, Q -bis-maltosides with aliphatic two-, three-, or four-earbon spacers were synthesized [183]. Spaced cyclodextrins were prepared to study their supramolecular properties [184,185]. 

Finally there are two very slow phases with lifetimes of 225 ms and 5.5 s, respectively. These phases have been attributed to P700 reduction by reductants present in the medium, as they are negligible and only observed in the absence of reduced DCIPH2. The PS-I complex prepared with -dodecyl-(3-D-maltoside ( 3-DM) shows very similar kinetic phases over the three time domains (not shown). Also,... 

Preparation of phenyl-2,3,6,2, 3, 4 -hexa-0-benzyl-l-thio-P-D-maltoside. 

Thylakoids were prepared from wheat and pea leaves as described previously (7). PSII reaction centres were prepared from Triton X-lOO-solubilised pea thylakoids and exchanged into "maltoside buffer" (2 mM dodecyl maltoside in 50 mM Tris-Cl pH 7.2) as described elsewhere (8). 

The reaction centre complex as prepared by the method of Nanba and Satoh (1) is unstable. Increased stability of the complex occurs when the Triton X-100 is exchanged for a detergent such as dodecyl maltoside (3,4). 

The PSII reaction centre was isolated as described in ref. 1. In the initial experiments the samples contained Triton-XlOO, but in later measurements dodecyl maltoside replaced the Triton. No difference was observed between the two preparations in EPR kinetics. The samples were diluted with 50 mM tris-HCl pH 8.0 to a concentration of 80 ig chl/ml. 10 mg/ml Na dithionite was added. After dark adaptation, the samples were cooled rapidly in complete darkness to 77 K. 

Prochlorothrix culture and preparation of thylakoids was as described before (4,6). Absorbance spectra were obtained on an Aminco DW 2000 spectrophotometer. Fluorescence spectra were made on a laboratory assembled instrument. Two phase partioning separation was done as in (9). Maltoside and Zwittergent application followed published procedures (6, 10). SDS- PAGE was as in (6). HPLC analysis of chi a and b was as described in (7). Chi to P7 q o i atios were estimated from ferricyanide/ ascorbate difference spectra. 

Maltoside solubilization as in (7) rendered a PS I complex similar to the Triton X-100 preparation. 

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