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Difference between revisions of "Glycoside Hydrolases"

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* Author: [[User:Williams|Spencer Williams]]
#REDIRECT [[Glycoside hydrolases]]
* Responsible Editor:  [[User:Williams|Spencer Williams]]
== Overview ==
Glycoside hydrolases are enzymes that catalyze the hydrolysis of the glycosidic linkage of glycosides, leading to the formation of a sugar hemiacetal or hemiketal and the corresponding free aglycon. Glycoside hydrolases are also referred to as glycosidases. Glycoside hydrolases can catalyze the hydrolysis of O-, N- and S-linked glycosides.
== Classification ==
Glycoside hydrolases can be classified in many different ways. The following paragraphs list several different ways, the utility of which depends on the context in which the classification is made and used.
''exo''- and ''endo''- refers to the ability of a glycoside hydrolase to cleave a substrate at the end (most frequently, but not always the non-reducing end) or within the middle of a chain. For example, most cellulases are ''endo''-acting, whereas LacZ β-galactosidase from ''E. coli'' is ''exo''-acting.
EC numbers are codes representing the Enzyme Commission number. This is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme. EC numbers do not specify enzymes, but enzyme-catalyzed reactions. If different enzymes (for instance from different organisms) catalyze the same reaction, then they receive the same EC number. A necessary consequence of the EC classification scheme is that codes can be applied only to enzymes for which a function has been biochemically identified. Additionally, certain enzymes can catalyze reactions that fall in more than one class. These enzymes must bear more than one EC number.
Retaining and inverting classification refers to the stereochemical outcome of the hydrolysis reaction catalyzed by the glycoside hydrolase. Retaining enzymes produce a product with the same stereochemistry as the glycoside substrate , and inverting enzymes give a product with the opposite stereochemistry to the glycoside substrate.
== Mechanism ==
== Sequence-based classification ==
== Glycoside Hydrolase Firsts ==
;First sterochemistry determination: Cite some reference here, with a ''short'' explanation <cite>1</cite>.
;First catalytic nucleophile identification:
;First general acid/base residue identification:
;First 3-D structure:
== References ==
#1 pmid=17323919
Category:Glycoside Hydrolase Families

Latest revision as of 02:00, 29 September 2009