This book delves into the correlation between different enzymes and neurodegenerative disorders. It investigates the intricate processes that contribute to the decline of cognitive functions, memory impairment, and other incapacitating symptoms of Alzheimer's disease. The book examines the roles of diverse enzymes in Amyotrophic Lateral Sclerosis and their effects on the motor neurons, leading to muscle weakness, paralysis, and eventual fatality. Moreover, it examines the association between depression and the enzymes responsible, providing a fresh viewpoint on the biochemical foundation of this ailment. Lastly, the book explores the connection between enzymes and Parkinson's disease, discussing the mechanisms that cause the death of dopamine-producing neurons and the related symptoms. By examining the functions of various enzymes in Parkinson's disease, the book presents a distinct outlook on the intricate interplay between enzymes and several neurological conditions, imparting readers with a comprehensive understanding of the fundamental mechanisms that underlie these disorders.