Catalyzes the decarboxylation of L-aspartate, 3-sulfino-L-alanine (cysteine sulfinic acid), and L-cysteate to beta-alanine, hypotaurine and taurine, respectively. The preferred substrate is L-aspartate. 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 Activated weakly by 0.2-0.4 mM Li(+). Inhibited by bis-carboxymethyl-trithiocarbonate, ethylxanthogenacetic acid and 2,5-disulfoaniline. kcat is 3.6 sec(-1) with 3-sulfino-L-alanine (cysteine sulfinic acid) as substrate. kcat 1.3 sec(-1) is with L-aspartate as substrate. Homodimer. Expressed in skeletal muscles and kidney (at protein level). Expressed in skeletal muscle and weakly in brain. Not expressed in liver or kidney. Expressed in brain, olfactory bulb, liver, muscle and kidney with the highest expression in olfactory bulb and almost not detected in liver (at protein level) (PubMed:26327310). Expression in total brain lysate is weak but seems to decrease with age as detected from 17 dpc to 12 months. Belongs to the group II decarboxylase family.