BCAT1 (Branched Chain Amino Acid Transaminase 1) is an important enzyme that helps regulate the metabolism of branched-chain amino acids (BCAAs) — leucine, isoleucine, and valine. It primarily works in the cytosol of brain tissues and certain tumors, where it catalyzes the reversible conversion of BCAAs into their α-keto acids, starting their breakdown process. BCAT1 plays a key role in maintaining nitrogen balance and supporting neurotransmitter production, which influences brain function and development. Additionally, BCAT1 is involved in cancer cell growth and metabolism, making it a potential biomarker for some cancers.