Excess S-Adenosylmethionine inhibits methylation via catabolism to adenine

An interesting piece about SAMe, AHCY and circadian rhythm.

Excess S-Adenosylmethionine inhibits methylation via catabolism to adenine:

Here, using biological rhythms to assess the effects of exogenous S-adenosylmethionine, we reveal that excess S-adenosylmethionine disrupts rhythms and, rather than promoting methylation, is catabolized to adenine and methylthioadenosine, toxic methylation inhibitors.

These findings further our understanding of methyl metabolism and question the safety of S-adenosylmethionine as a supplement. (R1)

Relation to circadian rhythm

This link between methylation and circadian rhythms was found in many eukaryotic cells, from unicellular green algae to human cells. These studies concluded that disrupted biological rhythms can be used as a reliable and quantitative sign of methyl metabolism deficiency, with the circadian period increasing proportionally with the concentration of AHCY inhibitors. (R1)