The crude enzyme, which was extracted from viscera of Lunella coronata coreensis (Recluz), was salted out and dialysed. Three enzymatic peaks isolated from DEAE-cellulose column chromatography were refered to as lyase Ⅰ, Ⅱ and Ⅲ, respectively. Then these lyases underwent gel-filtration on Sephadex G-25 respectively, and three purer lyases were derived therefrom, the highest purification being 73 fold.The kinetics of the three lyases was tested respectively. The optimum pH was as follows: lyase Ⅰ was 7.6±0.02 Tris-HCl buffer; lyase Ⅱ was 6.6±0.02 Na2HPO4-NaH2PO4 buffer; and lyase Ⅲ was 5.6±0.02 HAc-NaAc buffer. In the rang of tested concentration, KC1 and Nad were the activator and MnCl2 was the inhibitor, all for the three lyases; MgCl2 was the activator for lyases Ⅰ and Ⅱ, but the MgCl2 of high concentration was the inhibitor for lyase Ⅲ; Pb (OAc)2 acted differently for three lyases. The Km values of these lyases were 0.2, 0.6 and 0.04 mg/ml in order of precedence. The crude enzyme, which was extracted from viscera of Lunella coronata coreensis (Recluz), was salted out and dialysed. Three enzymatic peaks isolated from DEAE-cellulose column chromatography were refered to lyase I, II and III, respectively. Then these lyases underwent gel-filtration on Sephadex G-25 respectively, and three purer lyases were derived from, the highest purification being 73 fold. The kinetics of the three lyases were individually tested. The optimum pH was as follows: lyase I was 7.6 ± 0.02 Tris- Lyase Ⅱ was 6.6 ± 0.02 Na2HPO4-NaH2PO4 buffer; and lyase Ⅲ was 5.6 ± 0.02 HAc-NaAc buffer. In the rang of tested concentration, KC1 and Nad were the activator and MnCl2 was the inhibitor, all for the three lyases ; MgCl2 was the activator for lyases I and II, but the MgCl2 of high concentration was the inhibitor for lyase III; Pb (OAc) 2 acted differently for three lyases. The Km values ​​of these lyases were 0.2, 0.6 and 0.04 mg / ml in order of precedence .