S-(5′-Adenosyl)-L-homocysteine is primarily used in biochemical research to study enzyme mechanisms, particularly those involving methyltransferases. It serves as a key intermediate in the methylation process, helping researchers understand metabolic pathways related to DNA, RNA, and protein methylation. Additionally, it is utilized in the development of inhibitors for enzymes like SAH hydrolase, which are potential targets for antiviral and anticancer therapies. Its role in regulating methylation reactions makes it valuable for investigating epigenetic modifications and their impact on gene expression.