Why can't the essential amino acids be produced in the body even though they are coded by the DNA?

essential amino acids are the group of the 20 amino acids commonly found as constituents of mammalian proteins
If the genetic code for the essential amino acid is present then why do we need to obtain them from our diet?

1 Answer
Nov 16, 2017

Wrong premise...

Explanation:

Amino Acids are NOT coded for in our DNA: They are used as building blocks for the synthesised protein during Translation.

The human body CAN synthesise some amino acids from other biomolecules, primarily in the liver, like Alanine, Aspartate and Glutamate, but not all of them.
That's why we rely on our diet for an adequate supply, especially as some of these proteinogenic AA's have other functions as well, e.g. Neutrotransmitters (Tyrosine, Tryptophane, Glutamate).

Interesting fact: GGT, AST and ALT (Gamma Glutamyl Transferase, ASpartate Transaminase and ALanine Transaminase) are standard in a Liver Function Test:
As liver cells "explode", their contents are released into the bloodstream.
The GGT, ALT and AST concentrations in the bloodstream are therefore an indication of the status of the liver. More importantl;y, the ratio of their concentrations is an indicator for chronic alcoholism...