摘要：Cytochrome P450 OleT_(SA),a new cytochrome P450 enzyme from Staphylococcus aureus,catalyzes the oxidative decarboxylation and hydroxylation of fatty acids to generate terminal alkenes and fatty *** mechanism of this bifurcative chemistry remains largely ***,a class of derivatized fatty acids were synthesized as probes to investigate the effects of substrate structure on the product type of P450 OleT_(SA).The results demonstrate that the fine-tuned structure of substrates,even in a remote distance from the carboxyl group,significantly regulates OleT catalyzed decarboxylation/hydroxylation *** docking analysis indicated the potential interactions between the carboxylate groups of different probes and the enzyme active center which was attributed to the bifurcative chemistry.

摘要：为研发生态导向型盐碱地治理修复技术解决黄河河套宁夏平原土壤盐碱化,设计不同水平生物基磺酸盐改良剂用量(0、750、1 500、2 250、3 000kg·hm^(-2))进行盆栽试验。结果表明,生物基磺酸盐改良剂可有效降低盐碱土pH和全盐质量分数,促进油葵生长发育,但施用量过高会起到相反作用。当生物基磺酸盐改良剂施用量为2 250kg·hm^(-2)时改良效果最佳:油葵蕾期土壤pH、全盐质量分数最低达到9.63和0.77g·kg^(-1),较对照(CK)分别下降6.14%和62.07%;油葵叶片抗氧化保护酶过氧化氢酶(CAT)和过氧化物酶(POD)活性最高达到90.15 U·g^(-1)·min^(-1)和127.00μg·g^(-1)·min^(-1),较对照分别提高83.12%和117.58%;叶片叶绿素质量分数、净光合速率最高达到1.67mg·g^(-1)和26.91μmol·cm^(-2)·min^(-1),较对照分别提高38.02%和19.97%;油葵叶片的膜脂过氧化产物丙二醛(MDA)质量摩尔浓度最低达到6.34mmol·g^(-1),较对照降低25.06%;油葵株高也在该处理达到最高,且与其他处理差异显著。因此,生物基磺酸盐改良剂可较好地改良宁夏平罗西大滩盐碱化土壤,其最佳施用量为2 250kg·hm^(-2)。