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Difference between revisions of "Carbohydrate-active enzymes"
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Enzymatic formation and cleavage of the bond between two sugars or between a sugar and another group can occur by hydrolysis to give the free sugar (''glycosidases'' or ''glycoside hydrolases''), by transglycosylation to give a new glycoside (''transglycosidases''), by phosphorolysis to give the sugar-1-phosphate (''phosphorylases'') or by elimination to give unsaturated sugar products (''lyases''). The principal enzymes that catalyze glycoside synthesis are nucleotide phosphosugar-dependent ''glycosyltransferases''. | Enzymatic formation and cleavage of the bond between two sugars or between a sugar and another group can occur by hydrolysis to give the free sugar (''glycosidases'' or ''glycoside hydrolases''), by transglycosylation to give a new glycoside (''transglycosidases''), by phosphorolysis to give the sugar-1-phosphate (''phosphorylases'') or by elimination to give unsaturated sugar products (''lyases''). The principal enzymes that catalyze glycoside synthesis are nucleotide phosphosugar-dependent ''glycosyltransferases''. | ||
| + | Sequence analysis methods allow the grouping of proteins into sequence-related families. Sets of sequence-related enzymes are termed families. Sequence analysis groups ''transglycosidases'' with ''glycoside hydrolases'' (e.g. Family GH13 cyclodextrin glucanotransferases and amylases). According to all available evidence ''transglycosidases'' and ''glycoside hydrolases'' use the same mechanism, except that a sugar or some other group, rather than water, acts as the nucleophile. | ||
== References == | == References == | ||
Revision as of 03:04, 9 July 2009
Enzymatic formation and cleavage of the bond between two sugars or between a sugar and another group can occur by hydrolysis to give the free sugar (glycosidases or glycoside hydrolases), by transglycosylation to give a new glycoside (transglycosidases), by phosphorolysis to give the sugar-1-phosphate (phosphorylases) or by elimination to give unsaturated sugar products (lyases). The principal enzymes that catalyze glycoside synthesis are nucleotide phosphosugar-dependent glycosyltransferases.
Sequence analysis methods allow the grouping of proteins into sequence-related families. Sets of sequence-related enzymes are termed families. Sequence analysis groups transglycosidases with glycoside hydrolases (e.g. Family GH13 cyclodextrin glucanotransferases and amylases). According to all available evidence transglycosidases and glycoside hydrolases use the same mechanism, except that a sugar or some other group, rather than water, acts as the nucleophile.
References
- Comfort DA, Bobrov KS, Ivanen DR, Shabalin KA, Harris JM, Kulminskaya AA, Brumer H, and Kelly RM. (2007). Biochemical analysis of Thermotoga maritima GH36 alpha-galactosidase (TmGalA) confirms the mechanistic commonality of clan GH-D glycoside hydrolases. Biochemistry. 2007;46(11):3319-30. DOI:10.1021/bi061521n |
[[Category:Glycoside Hydrolase Families]]