Question:medium
Which of the following liver enzymes is predominantly mitochondrial?
Which of the following liver enzymes is predominantly mitochondrial?
Show Hint
This transaminase has both cytosolic and mitochondrial isoenzymes.
Updated On: Jun 24, 2026
- SGOT (AST)
- SGPT (ALT)
- GGT
- 5'-Nucleotidase
Show Solution
The Correct Option is A
Solution and Explanation
The trick here is to know which liver enzyme keeps a big share of itself inside mitochondria rather than floating in the cytoplasm or sitting on membranes.
AST, the old SGOT, comes in two flavors: one in the cytosol and one in the mitochondria, and the mitochondrial fraction is substantial in the liver. That is why severe, deep hepatocyte damage, such as in alcoholic hepatitis, spills extra AST and pushes the AST-to-ALT ratio above two. ALT, the old SGPT, lives almost entirely in the cytosol, which makes it more liver-specific but firmly non-mitochondrial.
The remaining two are membrane enzymes, not mitochondrial at all. GGT is anchored to canalicular and microsomal membranes and rises with cholestasis and enzyme induction. 5'-nucleotidase is a plasma-membrane enzyme used to confirm that a raised alkaline phosphatase is of hepatic origin. So the only enzyme with a major mitochondrial home is AST.
\[\boxed{\text{SGOT (AST)}}\]
AST, the old SGOT, comes in two flavors: one in the cytosol and one in the mitochondria, and the mitochondrial fraction is substantial in the liver. That is why severe, deep hepatocyte damage, such as in alcoholic hepatitis, spills extra AST and pushes the AST-to-ALT ratio above two. ALT, the old SGPT, lives almost entirely in the cytosol, which makes it more liver-specific but firmly non-mitochondrial.
The remaining two are membrane enzymes, not mitochondrial at all. GGT is anchored to canalicular and microsomal membranes and rises with cholestasis and enzyme induction. 5'-nucleotidase is a plasma-membrane enzyme used to confirm that a raised alkaline phosphatase is of hepatic origin. So the only enzyme with a major mitochondrial home is AST.
\[\boxed{\text{SGOT (AST)}}\]
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