Nitrilase that hydrolyzes preferentially aliphatic nitriles like malononitrile and fumaronitrile in vitro. These dinitriles are converted to the corresponding monoacid mononitriles, showing the enzyme is regioselective. Cannot hydrolyze compounds with a nitrile group bound to an aromatic ring or amino acid. Its biological role is unknown. a nitrile + 2 H2O = a carboxylate + NH4(+) Enzymatic activity is inhibited in the presence of acetone, methanol and metal ions such as Ag(2+) and Hg(2+). Is also inhibited by various thiol reagents such as DTNB, p-chloromercuribenzoate, p-hydroxymercuribenzoate, iodacetamide and iodacetate. EDTA has no influence on activity. Optimum pH is 7.4. Active within the pH range of 4.5-8.5. Optimum temperature is 80 degrees Celsius. Active at a broad temperature range (60-90 degrees Celsius). Highly thermostable with a half-life of 25 hours at 70 degrees Celsius, 9 hours at 80 degrees Celsius, and 6 hours at 90 degrees Celsius. Shows a Tm of 112.7 degrees Celsius. Homodimer. Belongs to the carbon-nitrogen hydrolase superfamily.