P-Cellobiosyl fluoride

Among other in vitro enzymatic polymerizations that have been studied are the oxidative polymerizations of 2,6-disubstituted phenols to poly(p-phenylene oxide)s (Sec. 2-14b) catalyzed by horseradish peroxidase [Higashimura et al., 2000b] and the polymerization of P-cellobiosyl fluoride to cellulose catalyzed by cellulase [Kobayashi, 1999 Kobayashi et al., 2001],... 

Amphiphilic cyclodextrins 56 have been synthesized in high yields in one step from the corresponding bromides 55. In a similar preparation of peracetylated heptakis [6-S-(2,3-dihydroxypropyl)-6-thio]-P-cyclodextrin (58), the heptakis iodide 57 was used as precursor. Oxidation with MCPBA furnished heptakis sulfone 59. Hemithiocyclodextrins (cyclodextrins in which half of the inter-glycosidic oxygen atoms are replaced by sulfur atoms) and hemithiocellodextrins have been obtained in yields of ca. 10 % by exposure of 4-thio-a-maltosyl fluoride to cyclodextringlycosyltransferases and 4-thio-P-cellobiosyl fluoride to cellu-lases, respectively. 

Kobayashi and co-workers [218] reported that cellulose I and cellulose II can be selectively synthesised in vitro using the enzymatic polymerisation of the P-cellobiosyl fluoride monomer, and this selectivity could be controlled by changing the enzyme purity and polymerisation conditions. 

The details of the synthesis method are as follows A substrate monomer of p-cellobiosyl fluoride first synthesized and purified (10.3 mg, 2.9 x 10" mol purity 95%) was solubilized in 170 pi of acetate buffer in D2O (CH3COOH/ CH3C00Na/D20) (pD = 5.0, 0.05 M). To this solution acetonitrile (1000 pi) was added. D2O was used to enhance the scattering contrast for SANS and USANS from the self-assembled cellulose molecules and enzymes against the reaction medium as well as to reduce the incoherent scattering intensity level of the system. The polymerization was started by mixing the above solution, designated as solution A, with 30 pi of acetate buffer in D2O (pD = 5.0,... 

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