LIVER ENZYMES Flashcards
Aspartate Aminotransferase (AST) is involved in the ________ and _______ of Amino Acids in the ______
synthesis (anabolism) , degradation (catabolism), liver
TRUE OR FALSE
Aspartate Aminotransferase (AST)Aspartate Aminotransferase (AST) is liver SPECIFIC
FALSE. It is NOT LIVER SPECIFIC
Aspartate Aminotransferase (AST) is widely distributed, highest activities in _____, _____, and _____
cardiac, liver, skeletal muscle
Aspartate Aminotransferase (AST)
2 isoenzymes
- Cytoplasmic AST
- .Mitochondrial AST
predominant; has higher conc. in serum than the other AST; released in cell membrane damage
Cytoplasmic AST
AST that is elevated in severe injury/ damage to cell
Mitochondrial AST
After MI, AST levels begin to rise in ______, peak at _____, and return to normal in ______
6-8 hours, 24 hours, 5 days
In the case of MI, is AST the fastest to rise? If not, what enzyme?
NO!!! Creatine Kinase and Troponins are faster than AST
Uses malate dehydrogenase and monitors decrease in absorbance at 340 nm because NAD is oxidized (no end color)
KARMEN METHOD
KARMEN METHOD primary enzyme
AST (serum)
KARMEN METHOD in hemolyzed sample
falsely elevated
KARMEN METHOD reference range
5–30 u/L
Aspartate Aminotransferase (AST) is also known as
Serum glutamic-oxaloacetic transaminase (SGOT)
Alanine Aminotransferase (ALT) is also known as
serum glutamic-pyruvic transaminase (SGPT)
Enzyme that is more liver specific; significant in assessing liver disorders
Alanine Aminotransferase (ALT)
Alanine Aminotransferase (ALT)
substrate
Alanine
Aspartate Aminotransferase (AST) substrates and products
Substrates: aspartate & a-ketoglutarate
Products: glutamate & oxaloacetate
Alanine Aminotransferase (ALT)
substrates and product
Substrate: alanine & a-ketoglutarate
Product: glutamate & oxaloacetate
Increased in hepatocellular disorders (hepatitis & cirrhosis)
Alanine Aminotransferase (ALT)
Marker for Hepatic Disorders: Acute inflammatory conditions of the liver
Alanine Aminotransferase (ALT)
Aside from ______, _____ is also useful in monitoring the course of hepatitis treatments
(_____ → + Treatment Response)
bilirubin, ALT
⬇ ALT
ALT is also a more sensitive and specific screening test for patients with _______ and _________
post-transfusion hepatitis (Hepatitis C), occupational toxic exposure
Differentiates the cause/ origin of hepatic disorder
De Ritis Ratio (Obsolete Method)
When AST (numerator) is greater, the ratio is more than 1
Ratio > 1 → Non-viral Origin (Higher AST)
When ALT (denominator) is greater, the ratio is less than 1
Ratio < 1 → Viral Origin (Higher ALT)
LDH Primary enzyme
Alanine Aminotransferase
LDH secondary enzyme
Lactate Dehydrogenase
LDH reference range
6-37 u/L
SGOT/ AST Major organ affected
Heart, Muscle, Liver
SGOT/ AST substrate
Aspartic Alpha
Ketoglutaric Acid
SGOT/ AST end products
Glutamic Acid +
Oxaloacetic Acid
SGOT/ AST and SGPT/ ALT Color Developer
2,4 DNPH (Dinitrophenylhydrazine)
SGOT/ AST and SGPT/ ALT Color Intensifier
0.4 N NaOH
SGOT/ AST and SGPT/ ALT Colorimetric Methods
Reitman and Frankel (colored end product)
SGPT/ ALT major organ affected
LIVER
SGPT/ ALT substrate
Alanine Alpha
Ketoglutaric Acid
SGPT/ ALT end products
Glutamic Acid +
Pyruvic Acid
Conditions of Increased AST
–AMI
–Wolff-Parkinson White
Syndrome (involuntary
muscle contraction)
–Trichinosis (T. spiralis)
–Chronic Alcoholism
–Dermatomyositis
–Muscular dystrophy
–Acute pancreatitis
Conditions of Increased AST & ALT
–Toxic Hepatitis (AST - ____; ALT - ______)
—Hepatic cancer (AST - ____ ALT - _____
–Reye’s Syndrome (____- more significant)
–Viral Hepatitis (____- more significant)
–Toxic Hepatitis (AST - chronic; ALT - acute)
—Hepatic cancer (AST - chronic; ALT - acute)
–Reye’s Syndrome (ALT - more significant)
–Viral Hepatitis (ALT - more significant)
Conditions of Increased ALT
Acute Alcoholism
Catalyze the transfer of the γ-glutamyl residue from γ-glutamyl peptides to amino acids, H20, etc
Gamma-Glutamyltransferase (GGT)
______is primarily derived from glutathione (common donor)
y-glutamyl
Gamma-Glutamyltransferase (GGT)
SUBSTRATES
Glutathione & Amino Acid
Gamma-Glutamyltransferase (GGT) PRODUCTS
Glutamyl-peptide & L-cysteinylglycine
GGT is for diagnosis of __________ (bile duct, gallbladder, liver) & _________
hepatobiliary disorders, chronic alcoholism
Marker for the detection of occult (hidden) alcoholism
Gamma-Glutamyltransferase (GGT)
GGT is a sensitive marker for
ethanol intoxication
The absorbance of p-Nitroaniline (colored end-product) is measured at 405-420 nm
SZAS ASSAY
