Sugar specificities

The complementation experiments in which the A domain of a class 111 E-II is used as the phosphoryl group donor to the B domain of a second E-II molecule with either the same or different sugar specificity, while both are fixed in a membrane matrix, raises some intriguing issues about the association state of these proteins and the kinetics of their interactions. Do E-IIs form stable homologous complexes in the membranes If so, is it necessary to postulate the formation of stable heterologous complexes to explain, for example, the phosphorylation of the B domain of E. coli 11° by the A domain of ll , or can the data be explained by assuming a... 

Table 6.4 Some lectins commonly used in immobilized format for the purification of glycoproteins. The sugar specificity is listed, as are the free sugars used to elute the bound glycoprotein...

Lectin Source Sugar specificity Eluting sugar... 

Thalhammer, A., Everts, I., and Hollmann, M. (2002) Inhibition by lectins of glutamate receptor desensitization is determined by the lectin s sugar specificity at kainate but not AMPA receptors. Mol. Cell. Neurosci. 21, 521-33. 

Hydrogen, isotopes of, sugars specifically labeled with,... 

S phosphoenolpyruvate -f HPr <2> (<2> i.e. histidine-containing protein, phospho-HPr serves as a phosphoryl distributor to a number of different sugar-specific enzyme Ill/enzyme II complexes [3]) (Reversibility <2>... 

Table XII. Sugar Specificity for Induced Transformation of Mutarotase...

The sugar specificity of RNase Tx appears to require a 2 -hydroxyl group for the substrate because DNA is not attacked by RNase Tx. This is consistent with the intermediary formation of 2, 3 -cyclic phosphate and also with the finding that 2 -0-methylated guanylyl bonds in tRNA is resistant to the enzyme (48)- Holy and Sorm (49) found that RNase Tx did not attack L-guanosine 2, 3 -cyclic phosphate and L-inosine 2, 3 -cyclic phosphate. They found further that RNase Tx split 9-(a-L-lyxo-furanosyl)-hypoxanthine 2, 3 -cyclic phosphate but not the D-lyxofura-nose derivative, and they concluded that the substrate molecule was fixed at least to three regions of RNase Tx (50). 

Holy and Sorm (49, 50) observed that RNase T2, like RNase Ti, attacks 9-(/3-D-ribofuranosyl) and 9-(a-L-lyxofuranosyl) derivatives but not 9-(j8-L-ribofuranosyl) and 9-(a-D-lyxofuranosyl) derivatives. Also, like RNase RNase T2 is quite inactive on the phosphodiester bonds of the nucleotide with 2 -0-methyl ribose, such as 2 -0-methyl guanylic acid (96) or 2 -0-methyl cytidylic acid (86). Thus, the action of RNase T2 is in good accord with that of RNase Ti and RNase A on sugar specificity, which may be a common property throughout all RNases, producing 3 -phosphate via 2, 3 -cyclic phosphate. 

Name Molecular Wt. (Subunits) Sugar Specificity Blood Group. TyPe... 

Fig. 12 Representation of the antibiofouling and sugar-specific recognition of a zwitterionic polymer-brush-based surface containing concanavalin A. Reprinted, with permission, from [171]. Copyright (2010) American Chemical Society...

Senafi SB, Clarke DJ, Burchell B. Investigation of the substrate specificity of a cloned expressed human bilirubin UDP-glucuronosyltransferase UDP-sugar specificity and involvement in steroid and xenobiotic glucuronidation. Biochem J 1994 303(pt l) 233-240. 

Lectin name Source Sugar specificity Interacting antibody... 

Chromatographic characterization of sugar phosphates can be achieved by two different methods. First, you can usually detect the sugar portion of sugar phosphates by using sugar-specific reagents, such as the aniline-acid-oxalate spray... 

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