Enzyme which is a marker for mitochondria is

Only liver mitochondria contain glutamate dehydrogenase (GDH) which deaminates glutamate to alpha-ketoglutarate plus ammonia. So, all amino acids are first transaminated to glutamate, which is then finally deaminated (transdeamination). So glutamate dehydrogenase acts as the mitochondrial marker for liver cells.Ref: D M Vasudevan 7th edition Page no: 202