...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Animal Feed Science and Technology >Red clover polyphenol oxidase: Activation, activity and efficacy under grazing
【24h】

Red clover polyphenol oxidase: Activation, activity and efficacy under grazing

机译：红三叶草多酚氧化酶：放牧条件下的活化，活性和功效

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This study investigated red clover polyphenol oxidase (PPO), its: activity, activation from latent into active form, and whether grazing at different levels of herbage maturity could result in sufficient PPO activation to protect proteins and glycerol-based lipid in the rumen. Wild-type red clover with high PPO activity and a mutant red clover with low PPO activity were used in five experiments. Firstly to investigate activation of the latent red clover PPO enzyme either through: protease, substrate (ortho-diphenols), cell damage or chemically (sodium dodecylsulphate detergent) induced mediation. Secondly PPO's activity at a range of pHs were determined to show how activation method altered the enzymes activity. Finally whether grazing could activate latent PPO and ultimately result in protected protein and glycerol-based lipid in the rumen was investigated. Incubation of extracted red clover PPO enzyme with a range of ortho-diphenols in the presence of oxygen resulted in rapid conversion of the latent to the active form of PPO. This conversion was blocked by the addition of ascorbic acid suggesting that this mechanism requires formation of ortho-quinones. Cell damage was highly correlated with activation of latent PPO and the formation of protein-bound phenols due to mixing of the chloroplastic enzyme with the vacuolar substrate (ortho-diphenols). The potential for PPO activity to occur during grazing was investigated by measuring the oxygen concentration in red clover boluses and within the rumen and PPO's effect on protein and glycerol-based lipid within red clover boluses. There was a rapid depletion of oxygen from the rumen, limiting the potential for PPO activation and activity to occur to the period of mastication. PPO was shown to be activated in both wild-type and mutant red clover boluses, however, factors such as fibre content and maturity of the red clover herbage (PPO concentration) altered the efficacy of PPO to produce phenol-bound protein. As a result greater protection of glycerol-based lipid in this study was achieved with a prior conditioning (wilting) of the red clover.
机译：这项研究调查了红三叶草多酚氧化酶（PPO），其活性，从潜伏到活性形式的活化以及在不同牧草成熟水平上放牧是否可以导致足够的PPO活化以保护瘤胃中的蛋白质和甘油基脂质。在五个实验中使用了具有高PPO活性的野生型红三叶草和具有低PPO活性的突变型红三叶草。首先研究潜在的红三叶草PPO酶是通过蛋白酶，底物（邻二酚），细胞损伤或化学诱导的（十二烷基硫酸钠去污剂）介导的。其次，测定在一定pH范围内的PPO活性，以显示活化方法如何改变酶的活性。最后，研究了放牧是否可以激活潜在的PPO，并最终导致瘤胃中蛋白质和甘油基脂质的保护。在氧气存在下，将提取的红三叶草PPO酶与一定范围的邻二酚一起孵育，可将潜在的PPO快速转化为活性形式。该转化被抗坏血酸的添加所阻止，表明该机理需要形成邻醌。细胞损伤与潜在的PPO的激活和蛋白结合的酚的形成高度相关，这是由于叶绿体酶与液泡底物（邻二酚）混合引起的。通过测量红三叶草大剂量和瘤胃内的氧气浓度，研究了放牧期间发生PPO活性的可能性，以及PPO对红三叶草大剂量内蛋白质和甘油基脂质的影响。瘤胃中的氧气迅速耗竭，从而限制了PPO活化和活性发生在咀嚼期间的可能性。 PPO在野生型和突变型红三叶草药丸中均被激活，但是，诸如纤维含量和红三叶草的成熟度（PPO浓度）等因素改变了PPO产生酚结合蛋白的功效。结果，在该研究中，通过预先调节（枯萎）红三叶草，可以更好地保护甘油基脂质。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号