Sadenosüülhomotsüsteiin

Sadenosüülhomotsüsteiin, often abbreviated as SAH or AdoMet-homocysteine, is a naturally occurring molecule in the human body. It is a byproduct of the transmethylation cycle, a vital metabolic pathway. This cycle involves the transfer of methyl groups, which are essential for numerous biological processes such as DNA methylation, protein synthesis, and neurotransmitter production. Sadenosüülhomotsüsteiin is formed when S-adenosylmethionine (SAM), the primary methyl group donor, donates its methyl group to an acceptor molecule.

Following this methylation reaction, SAM is converted into SAH. SAH is then further metabolized into homocysteine and adenosine. Homocysteine is an amino acid that, in elevated levels, has been associated with various health concerns. The body typically recycles homocysteine back into methionine or converts it into cysteine through enzymatic processes. Adenosine is a nucleoside that plays roles in cell signaling and energy regulation.

The levels of SAH are closely regulated within cells. Elevated SAH levels can inhibit methyltransferase enzymes, thereby disrupting the transmethylation cycle and potentially leading to a cascade of metabolic dysfunctions. Factors such as genetic variations, nutritional deficiencies (particularly of B vitamins like folate and B12, which are cofactors in homocysteine metabolism), and certain medical conditions can influence SAH levels. Research continues to explore the precise role of SAH in health and disease.