한국산 무우로부터 anionic isoperoxidase인 isoperoxidase $A_2$를 $(NH_4)_2SO_4$ saturation, CM-Sephadex chromatography, DBAE-Sephacel chromatography, Sephadex G-100 gel filtration 등을 이용하여 정제하였다. 정제된 효소의 분자량은 SDS-PAGE와 Sephadex G-150 gel filtration에 의해 각각 43,000과 43,700으로 판명되었다. 정제된 isoperoxidase $A_2$는 guaiacol을 기질로 사용하였을 경우 Km값이 6.7mM이었으며 $H_2O_2$에 대하여는 1.38mM로 나타났고 optimum pH는 5.0이었다. 여러 phenolic compound의 효소에 대한 기질가능성을 조사한 결과, scopoletin, caffeic acid, esculetin, chlorogenic acid, ferulic acid 등이 기질로 사용되었고 Km값은 각각 0.17mM, 1.43mM, 5.5mM, 1.5mM, 0.67mM이었으며 o-dianisidine의 Km값은 0.63mM이었다. 정제한 $A_2$는 glycoprotein이었으며, RZ value가 1.5인 hemoprotein으로 추측된다.
An anionic isoperoxidase, named $A_2$, was isolated from Korean-radish (Raphanus Salivas L.) root. Purification of the enzyme was accomplished by using CM-Sephadex chromatography, DEAE-Sephacel chromatography and Sephadex G-100 gel filtration. The enzyme was glycosylated and its molecular weight was approximately 43,000 as determined by SDS-PAGE and 43,700 by Sephadex G-150 gel filtration. Isoperoxidase $A_2$was a hemoprotein that had RZ value$(A_{439}/A_{275})$ of 1.5. The Km values for guaiacol and $H_2O_2$ were 6.7 and 1.38 mM, respectively. The Km value against o-dianisidine was 0.63 mM. Optimal pHs and Km values were also determined for various phenolic compounds such as scopoletin, caffeic acid, esculetin, chlorogenic acid and ferulic acid.
