Purification of Rhodotorula gracilis D-amino acid oxidase.

A protocol is presented for preparing Rhodotorula gracilis D-amino acid oxidase in homogeneous form and in high yield in 3 to 4 days. The method takes advantage of (a) cell rupture by alternate freeze-thawing, (b) use of DEAE-Sepharose to bind contaminants, and (c) enzyme binding to a Mono S column. The D-amino acid oxidase isolated by this means has the same spectral and catalytic properties as the enzyme previously obtained, and possesses improved long-term stability.