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The only information I know is about deamination is that it occurs in the liver and kidney. But in which part of the cell does deamination occur? To which tissues is transamination specific, and in which part of the cell does it occur?

I have searched Google and Google books and have come across some information like L-Glutamate dehydrogenase occurs in both cytoplasm and mitochondria and transamination occurs in the cytoplasm of all cells. But they were not from authentic sources, so I am asking it here.

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According to David H. Vroon and Zafar Israili aminotransferases (transaminases) are widely distributed among tissues, and are found in both cytoplasm and mitochondria, although this may vary between different aminotransferases:

Aminotransferases catalyze the redistribution of nitrogen between amino acids and corresponding oxoacids participating in both protein metabolism and gluconeogenesis. They are ubiquitous in their cellular distribution.

Tissue activity for AST (aspartate aminotransferase) is as follows in decreasing concentration: heart, liver, skeletal muscle, kidney, pancreas, spleen, lung, and erythrocyte. Two distinct forms have been identified: a cytoplasmic, or soluble isoenzyme, and a mitochondrial isoform...

The distribution and relative tissue concentration of ALT (alanine aminotransferase) is similar but importantly different. Highest activity is found in the liver, followed by kidney, myocardium, skeletal muscle, pancreas, spleen, lung, and erythrocyte. ALT activity is found in the cytosol; organ- or organelle-specific isoenzymes have not been demonstrated. The concentration of ALT in hepatic cell cytoplasm is comparable to AST; however, a mitochondrial ALT isoform is not found. In all other tissues, ALT activity is significantly less than AST.

As regards deamination, there is a Wikipedia page for glutaminase, which indicates that it is found in the mitochondria of a variety of tissues. There are two isoforms, one especially active in the kidney, and the other in liver (although both are found in other tissues).

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The oxidative deamination takes place inside the mitochondria, because the glutamate dehydrogenase is localized in the mitochondria. About the transamination, I'm not sure if it occur inside the mitochondria or in the cytoplasm.

The information about the oxidative damination and the enzyme could be found at this link: http://www.bioinfo.org.cn/book/biochemistry/chapt17/sim2.htm

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  • $\begingroup$ Please add citations to support your answers. See the accepted answer to this question for a good example. Scientists (at least good ones) don't accept statements just on their face - they must be supported with evidence. If you are making a claim, back it up. $\endgroup$ – MattDMo Jul 4 '16 at 23:32

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