Phenyl-a-D-mannopyranoside

IC with bovine enzyme which is very similar to the human one. Inhibitor concentration for 50% inhibition. K of substrate (phenyl a-D-mannopyranoside). K of substrate (4-nitrophenyl a-D-manno-pyranoside). K of substrate (4-nitrophenyl D-glucosiduronic acid). K of substrate (4-nitrophenyl 2-acetamido-2-deoxy- o-glueoside). Inhibitors were chitotetraono-1,5-lactone and chitotetraose, respectively. 

D-Mannono-1,5-lactone68 gave a value of 0.07 mM for Kj with rat-epididymal a-D-mannosidase, compared with 12 mM for Km for p-nitrophenyl a-D-mannopyranoside,88 and 57 mM for phenyl a-D-mannopyranoside.65 With jack-bean a-D-mannosidase, the values... 

Since phenyl a-D-galactopyranoside did react, although slowly, it is apparent that this substance was converted to some intermediate common to it and the jS-D-galactopyranoside, or else it was degraded by a mechanism unique to itself. The conversion of phenyl /3-D-mannopyranoside to l,6-anhydro-/3-D-mannopyranose9 was effected with relative ease, whereas phenyl a-D-mannopyranoside reacted at about the same rate but the intermediate product, which was apparently not stabilized by 1,6-anhydride formation, underwent extensive destruction in the alkali.8... 

The degradation of phenyl a-D-mannopyranoside (XXXII) leads to the formation of tars. This compound possesses the requisite trans relation between the reactive groups on Cl and C2, although the theoretical intermediate, l,2-anhydro-/3-D-mannopyranose (XXXIII), would not be able... 

The template monomer was designed for imprinting by inclusion in the microgels formed, followed by hydrolysis during suspension in methanol/water (1 1, v/v). Thus, the boronic ester was split and phenyl-a-D-mannopyranoside 2 (Fig. 2) was removed, leaving free binding sites in the polymer network. 

Fig. 2. Phenyl-2,3 4,6-tetra-0-bis(4-vinylphenylboronyl)-a-D-mannopyranoside 1, phenyl-a-D-mannopyranoside 2, EGDMA 3, TRIM 4, and 2,5-di-0-methacryloyl-l,4 3,6-dianhydro-D-sorbitol 5...

Van Wauwe and coworkers182 studied the effect of various para-substituents on the binding of phenyl a-D-mannopyranosides to the lentil lectin. As with con A and the pea lectin, binding of p-substituted-phenyl a-D-mannopyranosides correlated fairly well with the Hammett substituent constant trH in which electron-releasing... 

Figure 2.2 Imprinting of phenyl a-D-mannopyranoside using (4-vinylphenyl)boronic acid. Formation of monomer-template complex (1) polymerization (2) cleavage and extraction of template (3) and rebinding (4).

By contrast, phenyl a-D-mannopyranoside under the same conditions gives only methyl a-D-mannopyranoside. It was suggested that neighboring group participation from the 2-oxygen atom produces 1,2-anhydro-D-mannopyranose, which then reacts with methoxide ion to give the methyl mannoside.219... 

Phenyl-a-D-mannopyranoside (7a) (6 g 23.4 mmol) and tris(4-vinylphenyl)boroxin (6.075 g 15.6 mmol) were heated in benzene with removal of the water by azeotropic distillation. After complete removal of water, the solvent was evaporated, and the residue was crystallized from diethyl ether. Yield 9.7 g (86%), m.p. 139 °C. 

The effect of the flexibility of the binding group on the resolving power of the polymers was also investigated exemplarily for boronic acids [10,47]. For this, nine different polymerizable boronic acids with different degrees of mobility between the boron and the polymerizable double bond were used, with phenyl-a-D-mannopyranoside as the template. As the mobility of the groups in the cavity increased, the selectivity in racemate resolution decreased. 

A simple procedure reported for the isolation of jack-bean a-D-mannosidase was based on affinity chromatography on agarose-immobilized benzidine. The influence of substituents on the hydrolysis of substituted phenyl a-D-mannopyranosides by a-D-mannosidase from Medicago sativa seeds has been investigated. As indicated by structure-activity relations, the electronic effect of the substituent has an influence on the rate of formation of the intermediate D-mannosyl-enzyme complex. This effect depends not only on the nature of the substituent, but also on its position meta or para) and on the temperature of the experiment. Hammett-type linear free energy relationships show that the reaction constant p changes its sign at ca. 27 °C. Substrates... 

Benzyloxycarbonylamino)-2-nitro-phenyl-a-D-mannopyranoside tetraacetate, synthesis of, 367 iV-Benzyloxycarbonylglycylleucylphenyl-alanine chloromethyl ketone, 202 Benzylpenicillin isocyanate, 532, 534, 535, 537... 

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