May catalyze the decarboxylation of L-aspartate, 3-sulfino-L-alanine (cysteine sulfinic acid), and L-cysteate to beta-alanine, hypotaurine and taurine, respectively. Does not exhibit any decarboxylation activity toward glutamate. H(+) + L-aspartate = beta-alanine + CO2 3-sulfino-L-alanine + H(+) = CO2 + hypotaurine H(+) + L-cysteate = CO2 + taurine Homodimer. Expressed very weakly in neurons and not detected in astrocytes, brain or liver. Belongs to the group II decarboxylase family. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus.