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hi, is AST PRESENT IN rbc?
The liver is an important site for Amino acid and ammonia metabolism. Transamination reactions are catalysed by transaminases or amino tranferases{ALT (Alanine Transaminase), AST(Aspartate Transaminase)}, which inter convert a pair of amino acids with a pair of keto acids. An increse in serum transaminase is thus a sign of liver injury and represents leakage from injured hepatocytes into the bloodstream.
 

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And coming to your question, I am not 100%sure about this information..but...
ALT is found only in the liver.
AST in found in heart, brain, muscle, RBC too...
But AST has two isotypes, one in the cytoplasm and one in the mitochondria..and usually most of it is locked inside the mitochondria and thus their importance in liver injury when they leak from the mitochondria.

So in RBC only the cyoplasmic isoeznyme of AST is found.
This can also explain the comparison of AST/ALT in alocholic and other cause of hepatitis.

Need some expert comment though...
 

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And coming to your question, I am not 100%sure about this information..but...
ALT is found only in the liver.
AST in found in heart, brain, muscle, RBC too...
But AST has two isotypes, one in the cytoplasm and one in the mitochondria..and usually most of it is locked inside the mitochondria and thus their importance in liver injury when they leak from the mitochondria.

So in RBC only the cyoplasmic isoeznyme of AST is found.
This can also explain the comparison of AST/ALT in alocholic and other cause of hepatitis.

Need some expert comment though...
AST is found in the liver, cardiac muscle, skeletal muscle, kidneys, brain, pancreas, lungs, leukocytes, and erythrocytes in decreasing order of concentration.

ALT is found primarily in the liver.

Significance of AST ratio ALT

Chronic liver disease and chronic alcoholic disease both cause liver damage. But in alcohlic liver disease AST ratio ALT reaches 2:1 or above because

The elevated AST-to-ALT ratio in alcoholic liver disease results in part from the depletion of vitamin B 6 (pyridoxine) in chronic alcoholics. ALT and AST both use pyridoxine as a co-enzyme, but the synthesis of ALT is more strongly inhibited by pyridoxine deficiency than is the synthesis of AST.

Alcohol also causes mitochondrial injury, which releases the mitochondrial isoenzyme of AST.
 
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