PANCREATIC ENZYMES Flashcards
PANCREATIC ENZYMES
▪
AMYLASE
LIPASE
AMYLASE (AMS)
EC
▪ E.C. 3.2.1.1
▪ 1,4-D-Glucan Glucanohydrolase
AMS function
▪ Breakdown of starch and glycogen to monosaccharides
AMS
▪ Activators:
Calcium and chloride
AMYLASE (AMS)
Tissue Sources
– Salivary glands
▪ Salivary AMS or ptyalin
– Acinar cells of the pancreas
▪ Pancreatic AMS
AMYLASE (AMS)
Properties
– MW_____
– Readily filtered by the
50,000 – 55,000
glomerulus
– initial digestion of starch by salivary AMS
▪ Inactivated in the______
– final digestion by pancreatic AMS
Mouth; stomach
Small intestine
AMYLASE (AMS)
Isoenzymes
P-type isoamylase
S-type isoamylase
Pancreas
P-type isoamylase that is predominant in Acute pancreatitis
P3
Stype AMS found in
▪ Salivary gland
▪ Lungs
▪ Fallopian tubes
AMYLASE (AMS)
Diagnostic Significance
What disease?
▪ Rise:
▪ Peak:
▪ Normalize:
– Acute Pancreatitis
5-8 hours after the onset of an attack
24 hours
3-5 days
AMYLASE (AMS)
Diagnostic Significance
– Acute Pancreatitis
– Salivary gland lesions (parotitis)
– Intra-abdominal diseases
Chronic alcohol ingestion results in the:
– Secretion of protein-rich pancreatic fluid that leads to the deposition of thickened protein plugs and obstruction of small pancreatic ducts
– Transient increase in the pancreatic exocrine secretion and contraction of the sphincter of Oddi
– Direct toxicity in the acinar cells
AMYLASE (AMS)
Diagnostic Significance
– persistent increase in serum amylase is seen without clinical symptoms
Macroamylasemia
LIPASE (LPS)
EC
▪ E.C. 3.1.1.3
▪ Triacylglycerol Acylhydrolase
LIPASE function
Hydrolyzes the ester linkages of fats to produce alcohols and fatty acids
LIPASE (LPS)
Tissue Sources
– Primarily in the pancreas
– Also present in liver, stomach, small intestine, white blood cells, fat cells and milk (Henry)
LIPASE (LPS)
Diagnostic Significance
– Almost exclusive to the diagnosis of____
▪ Rise:
▪ Peak:
▪ Persist for about
▪ ____rise suggests poor prognosis or pancreatic cyst
acute pancreatitis
4-8 hours after onset of an attack
24 hours
8-14 days
> 14 days
LIPASE (LPS)
Diagnostic Significance
– Found also in other intra-abdominal conditions
______
– Normal in conditions with_____
▪ Duodenal ulcers, perforated peptic ulcers, intestinal obstruction, acute cholecystitis
salivary gland involvement
LIPASE (LPS)
▪ MW :
▪ Enzymatic activity is specific for the fatty acid residues at positions _____of the TAG molecules
▪ Substrate must be an_____ for activity to occur
45,000
1 and 3
emulsion
LIPASE
▪ Reaction rate is accelerated by the presence of
colipase and bile salt
LIPASE (LPS)
– Inhibit serum lipase
▪ Proteins, bile acids, heavy metals, quinine, and phospholipids
LIPASE
– Reverse this inhibition
– Coenzyme that prevents inhibitory effects on lipase
▪ Colipases
Macroamylasemia
– AMS molecule combines with…
IgG or IgA
Causes of acinar cell injuriy
Duct instruction
Acinar cell injury
Defective intralcellular tarnsport
Activated enzymes in Acinar cell injury
Interstitial inflammation and edema
Protease - proteolysis
Lipase/ phospholipases. - fat necrosis
Elastase - hemorrhage
