Katayama K, Kobayashi T, Oikawa H, Honma M, Ichihara A
Department of Bioscience and Chemistry, Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Biochim Biophys Acta. 1998 May 19;1384(2):387-95. doi: 10.1016/s0167-4838(98)00040-5.
In cell-free extracts of Alternaria solani, an enzymatic activity converting prosolanapyrone II to solanapyrones A and D via oxidation and subsequent Diels-Alder reaction has been found. Chromatography with DEAE-Sepharose provided two active fractions, pools 1 and 2. The former fraction converted prosolanapyrone II to solanapyrones A and D in a ratio of 2.2:1 with optical purities of 99% and 45% ee, respectively. The latter fraction did so in a ratio of 7.6:1 with 99% and nearly 0% ee, respectively. The enzyme partially purified from pool 2 native molecular weight of 40-62 kD and a pl of 4.25. The high reactivity of prosolanapyrone III in aqueous solution and the chromatographic behavior of the enzyme in pool 2 suggest that a single enzyme catalyzes both the oxidation and Diels-Alder reaction.
在链格孢菌的无细胞提取物中，已发现一种酶活性，可通过氧化及随后的狄尔斯-阿尔德反应将原索拉纳吡喃酮II转化为索拉纳吡喃酮A和D。用DEAE-琼脂糖进行色谱分离得到两个活性级分，即级分1和级分2。前一个级分将原索拉纳吡喃酮II转化为索拉纳吡喃酮A和D的比例为2.2:1，光学纯度分别为99%和45%对映体过量。后一个级分转化比例为7.6:1，光学纯度分别为99%和几乎0%对映体过量。从级分2中部分纯化得到的酶，其天然分子量为40 - 62 kD，等电点为4.25。原索拉纳吡喃酮III在水溶液中的高反应活性以及级分2中酶的色谱行为表明，单一酶催化氧化反应和狄尔斯-阿尔德反应。
