Galactoside

A,-Carrageenan [9064-57-7, 9000-07-1 (k+ little of 2.)]. This D-galactose-anhydro-D or L-galactoside polysaccharide is ppted from 4g of Carrageenan in 600mL of water containing 12g of KOAc by addn of EtOH. The fraction taken, ppted between 30 and 45% (v/v) EtOH. [Pal and Schubert JAm Chem Soc 84 4384 1962.]... 

Abbreviations All, allyl MP, dimelhylaminopyridine or 2,4,6-trimelhylpyridine MOM, methoxy-methyl Piv, pivaloyl Tr, trityl other abbreviations are the same. Obtained accompanied with the 3,4-0-( methyl orthoacetyl)-a-D-galactoside the 0-deacetyl derivative was also reported. Inserted as a reference reaction. A mixture of two diastereoisomers. On hydrolysis (R = F), 3,6-dideoxy-3,6-difluoro-D-glu-copyranose is formed. Methanolysis gives methyl 3-deoxy-3-fluoro-a-D-galactopyranoside. 

The fact that ) -D-galactosidase from Escherichia coli is inactivated more rapidly in the absence of Mg than in its presence can be taken as evidence that the activation of the triazene 38, that is, formation of )5-D-galactosyl-methyldiazonium ion, proceeds without acid catalysis, because Mg is required for the proton-assisted catalysis of yS-D-galactoside hydrolysis by this enzyme.Additional evidence for the absence of acid catalysis in the de-... 

S-type lectins P-Galactoside-binding animal lectins with roles In cell-cell and cell-matrix interactions... 

D-Xylose (b) D-Glucose (c) D-Galactose (d) Methyl D-Xyloside (e) Methyl D-Glucoside and (f) Methyl D-Galactoside. (Redrawn from Refs. 4 and 5.)... 

Acidification with trichloracetic acid catalyses oxidation , the fractional increase in the rate coefficient per mole of acid added, viz. Ak/ko)/[sicid], being of the order of two. Strong catalysis by alkali metal acetates has been observed for several oxidations, e.g. of m-cyclohexane-l,2-diol °, formic acid , methyl mannoside and galactoside and several a-hydroxycarboxylic acids °. 

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