An anionic isoperoxidase, named A₂, was isolated from Korean-radish (Raphanus Sativas 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 A₂ was a hemoprotein that had RZ value (A_(439)/A_(275)) of 1.5. The Km values for guaiacol and H₂O₂ 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.