酸碱度对重组鱼腥藻脂肪氧合酶构象与活性的影响

以重组表达、纯化得到的鱼腥藻脂肪氧合酶为研究对象,通过测定鱼腥藻脂肪氧合酶在不同缓冲体系中分子构象的变化(主要研究二级结构,螺旋、折叠、转角和无序结构单元质量分数),分析了鱼腥藻脂肪氧合酶分子构象变化与不同缓冲体系之间的关系,探求鱼腥藻脂肪氧合酶构象变化与生物酶学特性之间的关系.研究结果表明,该酶的最适反应pH值为9,最稳定pH值为7;发现在不同缓冲体系中,鱼腥藻脂肪氧合酶的相对活性变化和螺旋结构、转角结构、无序结构有密切关系.在pH值为6～9时,酶活性与螺旋结构、转角结构总体呈正相关,但与折叠结构的质量分数变化呈负相关.最稳定的酶的二级结果是折叠结构、无序结构、螺旋结构和转角结构,其质量分数均在20％ ～30％.

Effect of Different pH on Activity and Conformation of Ana-rLOX

The conformations of Anabaena Sp. lipoxygenase (ana-rLOX), such as secondary structure, helical structure, turn structure, and disordered structure were studied in different pH buffers. The correlation between the activity and conformation of ana-rLOX was studied. The results showed that the optimal pH and the most stable pH of ana-rLOX were 9 and 7. The enzyme activity was correlated with the content of helical structure, turn structure, and disordered structure. The enzyme activity positively correlated with the helical structure and turn structure while the enzyme activity negatively correlated with the disordered structure under the pH value between 6 and 9. The enzyme was most stable when the contents of helix, sheet, turn, and random structures were 20%-30%.