CC2 LEC - WEEK 1 (PT.3 GAMMA-GLUTAMYL TRANSFERASE)

GGT

catalyzes the transfer of glutamyl moiety from peptides to amino acids, other peptides, or water molecules

GGT

are plasma membrane bound on cells that has high secretory or absorptive properties

GGT

used as determinant of the current status of liver specifically biliary tree

7-10 days

half life of GGT

28 days

half life of GGT in alcoholic liver disease, increases to _________

1. szasz assay

2. IFCC reference method

2 measurement of GGT

szasz assay

what assay is GGT activity is measured by cleavage of chromogen o-carboxyl p-nitroaniline from a glutamate modified form of the compound.

L-y-glutamyl-3-carboxy-4-nitroanilide

IFCC substrate:

5-amino-2- nitrobenzoate

IFCC product:

glycyglycine

IFCC buffer and acceptor of rxn:

410nm, 37 degrees C

IFCC is measured at what wavelength and temperature?

1. liver damage

2. smoking

3. medications

4. liver tumors

5. obstructive jaundice

GGT is elevated in: (5)

liver damage

the major source of GGT release

chronic alcoholism

GGT is used as liver marker for _____________

levels by 10%

moderate smoking raises GGT levels by __________

by 20%

heavy smoking raises GGT levels by ___________

5 times normal

medications increase GGT levels up to _________

1. ethanol

2. phenytoin

3. barbiturates

4. carbamazepine

5. valproic acid

5 medications in GGT that increases the levels up to 5 times

post hepatic type of diseases

in obstructive jaundice, GGT is indicator of _________

cholestasis/ sclerosing cholangitis

in obstructive jaundice in GGT, _________________ beyond 10x upper limit of normal

1. pregnancy

2. oral contraceptives

GGT decreases in (2):

25% decrease in GGT levels

in GGT, first trimester of pregnancy causes _________ in GGT levels

reduction by 20% in GGT levels

in GGT, oral contraceptives causes ________ in GGT levels

1. evaluation of liver injury

2. test for alcoholic abuse

2 uses of GGT

evaluation of liver injury

primary use of GGT

lactate dehydrogenase

is a zinc-containing enzyme and its activity is part of the glycolytic pathway

acetyl coA

end product of lactate and pyruvate

tetramer of two active subnunits

LD is a ______________

heart, RBC, kidney

LD1 and LD2 is found in (3):

lungs, pancreas, spleen

LD3 is found in (3):

skeletal muscles, liver, intestine

LD4 and LD5 is found in (3):

serum

in LD, normal electrophoretic pattern is in _______

always higher

LD2 is ________ than LD1

100-225 U/L (forward reaction)

reference value of LD in forward reaction

80-280 U/L (reverse reaction)

reference value of LD in reverse reaction

lactate dehydrogenase

the 3rd enzyme to increase about 10hrs after the onset of signs and symptoms; it reaches its peak 3 days

LD 4 AND 5

what LD is: hepatic carcinoma and toxic hepatitis - 10 fold increase

1. wacker method (forward/direct)

2. wrobleski & la due (reverse/indirect)

3. heat denaturation

3 methods of determination in LD

heat denaturation

Used in differentiation of enzymes, applicable in separating LD1 (heat stable) to other isoenzymes

Wacker Method (forward/direct reaction)

what method of determination in LD is:

no assay and indicator reaction. The reaction itself has the oxidation/reduction of NAD to NADH

amylase/diastase

-Catalyzes the breakdown of starch (hydrolase)

-Smallest enzyme

-Earliest pancreatic marker

1. S-type (ptyalin)

2. P-type (amylopsin)

2 isoenzymes in amylase/diastase

s-type (ptyalin)

salivary amylase, released by salivary glands

s-type (ptyalin)

involves the breakdown of starch into dextrins which are shorter polysaccharide. This happens in the mouth

P-type (amylopsin)

pancreatic amylase, released by acinar cells of the pancreas

P-type (amylopsin)

involved in the breakdown of dextrins → maltose

60-180 SU/dL (Somogyi units)

95-290 U/L

reference value of amylase

6.0-.7.0

optimum pH of amylase

acute pancreatitis

caused by leakage of substances/ entry of acidic compounds directly coming from small intestine to pancreas

elevated up to 7 days

amylase in urine remains _____________

amylase

a small molecule readily filterable by the glomerulus; therefore it is excreted

1. diabetic ketoacidosis and renal insufficiency

2. macroamylasemia

3. medications

increase amylase (3):

Macroamylasemia

benign condition of geriatric age group wherein their amylase molecule is larger than normal and remains in the blood circulation for quite sometime.

low urine amylase

high serum amylase = ____ urine amylase

1. codeine

2. morphine

3. glucocorticoids

4. dexamethasone

5. oral contraceptives

5 medications in increase amylase

marker of pancreatic insufficiency

decrease amylase is a marker of _________

1. saccharogenic

2. amyloclastic

3. chronometric

4. amylometric

4 amylase determination

saccharogenic

measures the amount of reducing sugars produced by the hydrolysis of starch

Amyloclastic

amylase activity is evaluated by following the decrease in substrate concentration

chronometric

measures the time required for amylase to be completely hydrolyzed

amylometric

measures the amount of starch hydrolyzed in a fixed period of tim

calcium and chloride

2 activator in amylase determination

TAG, lipemic

2 interferences in amylase determination

lipase

An enzyme that hydrolyzes the ester linkages of fats to produce alcohol and fatty acids

free fatty acids + glycerol backbone

TAG = _____

lipase

most specific pancreatic marker

lipase

secreted exclusively in the pancreas, not affected by renal disorders

lipase

released by the gastrointestinal mucosa, RBCs and WBC

0-1.0u/L

reference value of lipase

7.8-8.0

optimum pH of lipase

1. cherry crandall method - classic method

2. colorimetric

2 lipase determination

cherry crandall method (classic method)

Hydrolysis of Olive Oil after incubation for 24 hrs @ 37C and titration of fatty acids using NaOH

50% olive oil (triolein)

substrate of cherry crandall method (classic method) in lipase determination

colipase and bile salts

to make the test more stable and more sensitive and specific for acute pancreatitis determination in to make the test more stable and more sensitive and specific for acute pancreatitis determination

fatty acid

end product of lipase in cherry crandall method (classic method)

colorimetric

copper + FA

1. bacteria contaminated sample

2. opiates and morpines

3. pancreatic duct obstruction and tumors of the pancreas

3 increases in lipase

false increase

bacteria contaminated sample in lipase can cause ___

increases lipase

opiates and morphines can ______

increases LPS activity due to its spastic effect on the duodenal musculature and Sphincter of Oddi

opiates and morphines

sphincter of oddi

gate which regulates exit of substances

1. lipemic specimen

2. hemolyzed specimen

3. pancreatic insuffiency

decrease LPS (3):

lipase

is the earliest enzyme marker, Amylase is the 2nd to increase in A.P

chronic acute pancreatitis

diagnostic significance of lipase

chronic acute pancreatitis

acinar cell degradation occurs resulting in loss of amylase and lipase production

Glucose-6-phosphate dehydrogenase

-oxidoreductase

-Catalyzes the oxidation of glucose-6-phosphate→ 6-phosphogluconate

Glucose-6-phosphate dehydrogenase

Important as the 1st step in the pentose phosphate shunt/hexose monophosphate pathway

Glucose-6-phosphate dehydrogenase

Used as one of the markers for newborn screening: G-6PD deficiency

Leucine Aminopeptidase (LAP)

Exhibits napthylamidase activity → enzyme attacks the free amino end of the peptide chain

Acyl βnapthylamide

substrate of Leucine Aminopeptidase (LAP)

rich in pancreas

Leucine Aminopeptidase (LAP) is rich in _______

1. serum

2. urine

3. bile sample

Leucine Aminopeptidase (LAP) is seen in (3):

marker of liver function

clinical significance of Leucine Aminopeptidase (LAP)

1. hepatobiliary disease

2. pancreatic cancer

3. last trimester of pregnancy

4. obstructive biliary disease

increase Leucine Aminopeptidase (LAP) can seen in (4):

Goldbarg-Rutenburg method

measurement of Leucine Aminopeptidase (LAP)

Goldbarg-Rutenburg method

β napthylamide reacts with ethylene diamine dihydrochloride blue end product

method of determination for leucine aminopeptidase

5' nucleotidase

Used to differentiate obstructive from hepatocellular jaundice and hepatobiliary from osseous disease

5' nucleotidase

To differentiate if patient has high ALP

1. post-hepatic jaundice

2. intrahepatic cholestasis

3. infiltrative lesions of liver

increased 5' nucleotidase can seen in (3):

hepatocellular jaundice

slightly increase 5' nucleotidase can seen in: