Human Adenosylhomocysteinase (AHCY) Protein

Background

AHCY, also known as S-adenosylhomocysteine hydrolase, is a critical enzyme in the methionine cycle that catalyzes the reversible hydrolysis of S-adenosylhomocysteine (SAH) into homocysteine and adenosine. This reaction is essential for maintaining cellular methylation reactions, as SAH is a potent inhibitor of methyltransferases. AHCY is ubiquitously expressed and localized in the cytoplasm and nucleus, where it regulates methylation-dependent processes such as DNA and histone modification, gene expression, and cell signaling. Dysregulation of AHCY leads to the accumulation of SAH, disrupting methylation and contributing to diseases such as homocystinuria, cardiovascular disease, and neurodegenerative disorders. Mutations in the AHCY gene can cause autosomal recessive hypermethioninemia. AHCY is also being studied as a potential target in cancer and metabolic disorders due to its pivotal role in methylation homeostasis.