Highly specific for beta-cyano-L-alanine (Ala(CN)). Low activity with 3-phenylpropionitrile (PPN) or allylcyanide and no activity with indole-3-acetonitrile. Not associated with auxin production but may be involved in cyanide detoxification. a nitrile + 2 H2O = a carboxylate + NH4(+) 3-cyano-L-alanine + 2 H2O = L-aspartate + NH4(+) L-asparagine = 3-cyano-L-alanine + H2O Both catalytic activities are inhibited by N-ethylmaleimide and are up-regulated during senescence. Optimum pH is 7-9 for both activities. Optimum temperature for both activities is 40 degrees Celsius. Forms a homopentamer composed of five dimers. Tightly associated with the plasma membrane. Belongs to the carbon-nitrogen hydrolase superfamily. Nitrilase family. Truncated N-terminus.