Sarcosine (Urine)

Sarcosine, or N-methylglycine, is an intermediate of the choline-to-serine catabolism sequence. It is formed by oxidative demethylation of dimethylglycine and it is then catabolized by further demethylation.

If Sarcosine is elevated in urine it suggests three possibilities.

1. Recent dietary supplementation of dimethylglycine, "DMG".

2. Deficiencies of the cofactors associated with sarcosine catabolism. These are folic acid as tetrahydrofolate, THF, and Vitamin B2, riboflavin, bound to the sarcosine dehydrogenase enzyme as FAD. The methyl group fragment removed from sarcosine is at the oxidative level of CHO and can form formaldehyde if tetrahydrofolate is insufficient. This would slow down sarcosine's catabolism while making it somewhat toxic.

3. Genetic weakness in sarcosine dehydrogenase with metabolic hypersarcosinuria and possibly hypersarcosinemia. Hereditary (severe) hypersarcosinuria is rare with an incidence of less than 1 in 40,000 newborns.

Unpublished clinical observations associate some cases of acquired, mild sarcosinuria (below 500 micromoles/24 hour) with past exposures to organic chemical solvent and petrochemicals. At such levels sarcosine itself is not known to be toxic. However, folic acid supplementation is suggested whenever sarcosine is elevated.

Sarcosine is also known as N-methylglycine. It is an intermediate and byproduct in the glycine synthesis and degradation. Sarcosine is metabolized to glycine by the enzyme sarcosine dehydrogenase, while glycine-N-methyl transferase generates sarcosine from glycine.