Amylase: Bishop

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Amylase: General Overview

Hydrolase enzyme

Function: Catalyze the breakdown of Starch and Glycogen

Starch is made up of:

Amylopectin -

Branched chain polysaccharide

has a 1,6-linkages at branch points

Amylose

long unbranched chain of glucose molecules

has a -1,4 - glycosidic bonds

Glycogen

similar structure of that of amylopectin

has more branching

Amylase only attacks the ________________ and produces degradation products:

Maltose

Intermediate chains

Glucose

these substances are called Dextrins

contains a - 1,6 branching linkages

Amylase does not attack Cellulose and other structural polysaccharides consisitng of linkages

This is the smallest enzyme

this is readily filtered by the glomerulous and appears in urine

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Tissue sources

Major Tissue sources:

Acinar cells of the pancreas

Secretes pancreatic AMY - performs major digestion action of starches once the polysaccaride reaches the intestine

Salivary glands

Secretes Salivary AMY - activity is short in duration - inactivated by gastric acidity

Smaller concentrations are found in:

Skeletal muscle

Small intestine

Fallopian tubes

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Isoenzymes

Serum AMY is a mixture of isoenzymes that can be separated by a number of physical properties:

Electrophoresis

Two major bands and minor bands can be seen

P type (P1,P2,P3)

derived from pancreatic tissue

increases during acute pancreatitis

P3 appears the most

this also appears in renal failure

non specific

predominates in normal urine

S type

derived from Salivary gland tissue

represents approximately 2/3 of normal serum

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Assay/Methods

Amyloclastic

AMY is allowed to act on starch substrate which is attached to iodine

Saccharogenic

Chromogenic

Continous monitoring

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Sources of error

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Diagnostic significance