Glycosidases, structure determination

To avoid the above mentioned problems which are due to side activities of commercial glycosidase preparations and the specificity of glycosidases for both, the glycon as well as the aglycon moiety, an isolation and structural determination of individual constituents in a precursor fraction should be attempted. This requires the availability of preparative separation techniques that enable a gentle isolation of reactive aroma precursors from the complex glycosidic fraction of wine. 

GH 2. The tetrameric lacZ (3-galactosidase of Escherichia coli has been intensively investigated for over 40 years, initially because of its relationship to Monod s classic work on enzyme induction. A very large set of data accumulated by Wallenfels and Weil unfortunately had to be discarded because it was obtained in inhibitory Tris buffers.The first glycosyl-glycosidase intermediate to become kinetically accessible was with this en-zyme the 2-fluoro-2-deoxy-a-D-galactopyranosyl enzyme, the parent enzyme and ES complexes have since been crystallised and its structure determined. 

Structural characterization of glycosidases has a long history, with the very first crystal structure of an enzyme being that of hen s egg white lysozyme. Of the current 112 families of glycosidases, more than 60 families already have at least one representative structure determined. An important feature emerging from these structural studies is the occurrence of widely diversified structural scaffolds, despite the fact that all these... 

B-Glucosidases and other glycosidases have been determined to often show an exceedingly high degree of specificity toward a particular substrate (2 ,n ). In recent work (12,13) this specificity has been shown to be attributable to the structure of the agiycone. 

Serological and enzymic techniques involving various glycosidases have been used for determining certain structural features of the secreted blood-group substances. Reviews of these data are available,241,285 and so these aspects will not be discussed. 

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