3-Aminopropionitrile fumarate salt is the fumarate salt of 3-aminopropionitrile, a compound widely used in biochemical and pharmacological research as an irreversible inhibitor of lysyl oxidase. This copper-dependent enzyme catalyzes the cross-linking of collagen and elastin in the extracellular matrix. By inhibiting lysyl oxidase, it is employed in studies of fibrosis, connective tissue remodeling, and diseases involving abnormal collagen formation, such as scleroderma and certain cancers. It also serves as a key intermediate in organic synthesis for producing pharmaceuticals and bioactive compounds. Additionally, it is utilized in animal models to induce lathyrism, facilitating research into musculoskeletal disorders and neurological conditions associated with collagen defects, such as spastic paraplegia.