Aspartate aminotransferases from ribbed mussel gill tissue: Reactivity with β- l-cysteinesulfinic acid and other properties

Abstract

1. 1. The β-form of the cytosolic aspartate aminotransferase (cAAT) and the mitochondrial aspartate aminotransferase (mAAT) from ribbed mussel ( Modiolus demissus = Gukensia demissa) gill tissue each exist as dimers of equal mol. wt (44,000). 2. 2. Both the cAAT and mAAT are reactive with β- l-cysteine sulfinic acid (CSA) as an amino donor substrate. 3. 3. The apparent K ms for CSA are very high (19–250 mM) and increase with decreasing pH.