Immobilized D-amino acid oxidase.

1. D-Amino acid oxidase (D-amino acid: oxygen oxidoreductase (deaminating), EC 1.4.3.3) apoenzyme, holoenzyme and the enzyme-benzoate complex were active and stable when immobilized to aminoalkyl or carboxyalkyl agarose, or to cyanogen bromide-activated agarose. The immobilized enzyme-benzoate complex could be converted into the holo- and apoenzyme without being liberated from the agarose. 2. The apparent Michaelis constant and substrate specificity of the immobilized enzyme were similar to those of the free enzyme. The optimum pH of the reaction was shifted towards acidic side by 1.0-2.0 pH units from that of the free enzyme. 3. With increasing number of methylene groups of the 'spacer' from 3 to 5, molecular activity of the immobilized enzyme increased, while the apparent Miachaelis constant decreased.