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S-Adenosylmethionine SAM Cycle

Meaning

The S-Adenosylmethionine (SAM) Cycle, often referred to as the Methionine Cycle, is a central metabolic pathway that produces and regenerates S-Adenosylmethionine, the universal methyl donor for nearly all biological methylation reactions. This cycle is critical for a vast array of physiological processes, including the methylation of DNA, histones, proteins, and neurotransmitters, which are all essential for proper gene expression and cellular communication. The efficiency of the SAM cycle is highly dependent on nutrient cofactors, such as folate and vitamin B12, and its function directly links nutritional status to the entire epigenetic landscape and hormonal metabolism.