초록
Saccharomycopsis lipolytica ATCC 44601에서 정제한 isocitrate lyase 반응산물의 축합반응과 개열반응은 $30^{\circ}C$, pH 7.0에서 분석되었다. Glyoxylate와 succinate의 축합반응에서 Km값은 각각 0.06 mM과 0.21 mM이었고, 개열 반응에서 glyoxylate는 직선적인 경쟁적 저해를, succinate는 직선적인 비경쟁적 저해를 나타내었으며 이때 Ki 값은 각각 0.22 mM과 0.82 mM이었다. 그러므로 이 kinetic분석은 이 효소가 축합 반응에서 glyoxylate가 succinate보다 먼저 결합하는 정서반응기구인 것을 나타내었다. 3-Bromopyruvate(BrP)의 불활성화는 포화 kinetics를 나타내면서 효소를 불가역적으로 불활성화하였으며 반감기는 0.15분이고 $K_{BrP}$는 0.032 mM이었으며, 기질과 반응생성물들을 불활성화에 대하여 보호작용이 있었다.
The analysis of condensation and cleavage reaction was carried out at $30^{\circ}C$ and pH 7.0 with purified isocitrate lyase from Saccharomycopsis lipolytica ATCC 44601. The Km values for condensation reaction of glyoxylate and succinate were 0.06 and 0.21 mM, respectively. In the cleavage reaction, glyoxylate was a linear competitive inhibitor with a Ki of 0.22 mM and succinate was a linear noncompetitive inhibitor with a Ki of 0.82 mM. Therefore, these kinetic analyses showed that the enzyme functioned in a ordered reaction with glyoxylate binding before succinate in the condensation reaction. 3-Bromopyruvate(BrP) was found to be irreversibly inactivation showing saturation kinetics, the inactivation half-time was 0.15 min and $K_{BrP}$ was 0.032 mM, and substrate or reactant protected against the inactivation.