The structure of human mitochondrial branched-chain aminotransferase

X-ray crystal structures of three forms of human mitochondrial branched-chain aminotransferase were solved by molecular-replacement methods. In two of the forms the enzyme is in its active form, with the pyridoxal 5′-phosphate (PLP) cofactor covalently linked to the ε-amino group of the active-site lysine. In the third form, a molecule of the Tris buffer is covalently bound to the PLP on one end and the active-site lysine on the other, inhibiting the enzyme irreversibly