1 Flashcards
Transfer of an amino group between aspartate
and α-keto acids
• Involved in the synthesis and degradation of AA.
• Widely distributed, highest activities in cardiac, liver
and skeletal muscle
Aspartate Aminotransferase (AST)
2 isoenxzyme:
______- most abundant / predominant in healthy human serum
________type: present in the mitochondrial membrane = inc. in serum= necrosis
Cytoplasmic
Mitochondrial
: enzymes with similar catalytic activity but defer in the physical and biochemical and immunologic properties
isoeznyme
Aspartate + a- ketoglutarate —- _____ ——oxaloacetate + glutamate
AST
AST
RISE
PEAK
RETURN TO NORMAL VALUES
6-8 hours
24 hours
5 days
AST also increase in
in hepatocellular and skeletal muscle dis
hepatocellular= chronic disorder of the liver with progressive damage
Uses malate dehydrogenase and monitors decrease in
absorbance at 340 nm
o Falsely ↑ in hemolyzed sample
Karmen method (AST)
RR of karmen method
5-30 U/L
aminotransferases need co enzyme;
_______ (vitamin B6)
Co-enzyme: this is a type of cofactor that serves as the second substrate for enzyme
when co enzyme is tightly bound it is called: ____ group
pyridoxal phosphate
prostetic
NAD 2 Forms
NAD- Oxidized - Decreased absorbance
NADH- Reduced - Increased absorbance
What Method
Aspartate + a-ketoglutarate
—> ______ —> glutamate + oxaloacetate
Oxaloacetate + NADH + H+—> _____ —>
malate + NAD*
KARMEN METHOD
AST
MD
WHAT IS THE PRODUCT IN KARMEN METHOD
OXALOACETATE/ NAD
Also known as serum glutamic-pyruvic transaminase
(SGPT)
• Transfer of an amino group between alanine and αketoglutarate
• Increased in hepatocellular disorder
Alanine Aminotransferase (ALT
more liver specific
ALT
is used/ sig in the eva of hepatic disorder
-inc in acyte inflammatory disorder of the liver
-used to monitor cause of the hepatitis treatement and effects of drug therapy
-use in screening for post tranfusion hepatitis
-screen for blood donors
ALT
Alanine + a-ketoglutarate
—> _____ —> pyruvate + glutamate
what is the product in this?
ALT
Glutamate
= sensitive test for occupational toxic exposure
ALT
The AST/ALT Ratio
• Differentiates the cause of hepatic disorder
Ratio > 1→
• Ratio < 1 →
DE RITIS RATIO
> 1 Non viral origin
< 1 Viral origin
Uses Lactate Dehydrogenase and monitors decrease in absorbance at 340 nm
ALT / DE RITIS RATIO
Alanine + a-ketoglutarate
—>____ —> pyruvate + glutamate
Pyruvate + NADH + H+
—> ___ —> Lactate + NAD always react with?
ALT
LD
reductase
MAJOR ORGAN AFFECTED IN AST AND ALT
HEART; LIVER
SUBSTRATE IN AST AND ALT
ASPARTIC ALPHA
KETOGLUTARIC ACID;
ALANINE ALPHA
KETOGLUTARIC ACID
END PRODUCTS OF AST and ALT
GLUTAMIC ACID +
OXALOACETIC ACID
GLUTAMIC ACID + PYRUVIC
ACID
COLOR DEVELOPER IN AST AND ALT
2,4 DNPH
2,4 DNPH
