Amylase: Difference between revisions

Line 19:

=Function=

==Mechanism==

In the human body, α-amylase is part of digestion with the breakdown of carbohydrates in the diet. The mechanism involved includes catalyzing substrate hydrolysis by a double replacement mechanism, forming a covalent glycosyl-enzyme intermediate and hydrolyzed through oxocarbenium ion-like transition states. One of the carboxylic acids in the active site acts as the catalytic nucleophile during the formation of the intermediate. A second carboxylic acid operates as the acid/base catalyst, supporting the stabilization of the transition states during the hydrolysis<ref name="human">PMID: 18284212</ref>.

In the human body, α-amylase is part of digestion with the breakdown of carbohydrates in the diet. The mechanism involved includes catalyzing substrate hydrolysis by a double replacement mechanism, forming a covalent glycosyl-enzyme intermediate and hydrolyzed through oxocarbenium ion-like transition states<ref name="human"/>. One of the carboxylic acids in the active site acts as the catalytic nucleophile during the formation of the intermediate. A second carboxylic acid operates as the acid/base catalyst, supporting the stabilization of the transition states during the hydrolysis<ref name="human">PMID: 18284212</ref>.

==Human Salivary and Pancreatic α-Amylase==

Salivary α-Amylase hydrolyzes the (α1-4) glycosidic linkages of starch, separating it into short polysaccharide fragments<ref name="Japan"> PMID: 16232518</ref>. Once the enzyme reaches the stomach, it becomes inactivated due to the acidic pH. Further breakdown of starch occurs by secretion of a second form of the enzyme by the pancreas. Pancreatic juice enters the duodenum and pancreatic α-amylase further cleaves starch to yield maltose, maltotriose and oligosaccharides<ref name="Japan"/>. The oligosaccharides are referred to as dextrins, which are fragments of amylopectin consisting of (α1-6)branch points<ref name="Japan"/>. Microvilli of the intestinal epithelia break maltose and dextrins into glucose, which gets absorbed into the circulatory system. Glycogen has a relatively similar structure as starch, and thus proceeds in the same digestive pathway.

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@@ Line 19: / Line 19: @@
 =Function=
 ==Mechanism==
-In the human body, α-amylase is part of digestion with the breakdown of carbohydrates in the diet. The mechanism involved includes catalyzing substrate hydrolysis by a double replacement mechanism, forming a covalent glycosyl-enzyme intermediate and hydrolyzed through oxocarbenium ion-like transition states. One of the carboxylic acids in the active site acts as the catalytic nucleophile during the formation of the intermediate. A second carboxylic acid operates as the acid/base catalyst, supporting the stabilization of the transition states during the hydrolysis<ref name="human">PMID: 18284212</ref>.
+In the human body, α-amylase is part of digestion with the breakdown of carbohydrates in the diet. The mechanism involved includes catalyzing substrate hydrolysis by a double replacement mechanism, forming a covalent glycosyl-enzyme intermediate and hydrolyzed through oxocarbenium ion-like transition states<ref name="human"/>. One of the carboxylic acids in the active site acts as the catalytic nucleophile during the formation of the intermediate. A second carboxylic acid operates as the acid/base catalyst, supporting the stabilization of the transition states during the hydrolysis<ref name="human">PMID: 18284212</ref>.
 ==Human Salivary and Pancreatic α-Amylase==
 Salivary α-Amylase hydrolyzes the (α1-4) glycosidic linkages of starch, separating it into short polysaccharide fragments<ref name="Japan"> PMID: 16232518</ref>. Once the enzyme reaches the stomach, it becomes inactivated due to the acidic pH. Further breakdown of starch occurs by secretion of a second form of the enzyme by the pancreas. Pancreatic juice enters the duodenum and pancreatic α-amylase further cleaves starch to yield maltose, maltotriose and oligosaccharides<ref name="Japan"/>. The oligosaccharides are referred to as dextrins, which are fragments of amylopectin consisting of (α1-6)branch points<ref name="Japan"/>. Microvilli of the intestinal epithelia break maltose and dextrins into glucose, which gets absorbed into the circulatory system. Glycogen has a relatively similar structure as starch, and thus proceeds in the same digestive pathway.