View source for 51. Disturbances of amino acid metabolism

These disorders are mostly congenital disorders, meaning the symptoms occur already from birth. Amino acids are important for the brain, so most of these cause mental problems. The most important disorders of amino acid metabolism are:

* Disorders of amino acid transport
** Hartnup disease
** Cystinuria
** Methionine malabsorption syndrome
* Disorders of amino acid metabolism
** Phenylketonuria
** Tyrosinosis
** Alkaptonuria
** Albinism
** Oxalosis
** Maple syrup urine disease
** Homocystinuria

Amino acids are transported into cells by active transport. Different transporter proteins exist for six types of amino acids:

* Group I – neutral amino acids – Ala, Ser, Tyr, Phe
* Group II – neutral amino acids – Met, Leu, Val, Ile
* Group III – Imino-acids – Gly, Pro, hydroxyproline
* Group IV – Acidic amino acids – Glu, Asp
* Group V – Basic amino acids – Lys, Arg, Orn
* Group VI – Cysteine

This means that for example glutamate and aspartate are transported by the same transporter proteins. Methionine, leucine, valine and isoleucine are all transported by the same transporter protein, and so on. This means that ''in theory'', if you consume very much of an amino acid in one group will the absorption of the other amino acids in the ''same'' group be competitively inhibited.

This is especially problematic if a lot of non-essential amino acids are consumed and not a lot of essential ones, potentially causing competitive inhibition of the absorption of the essential ones, causing deficiency. Like, if you consume a lot of alanine will you inhibit the absorption of the essential amino acid phenylalanine.