Polyphenol oxidase (PPO, E.C. 1.14.18.1) is a nearly ubiquitous enzyme that is widely distributed among organisms. Despite its widespread distribution, the role of PPO in plants has not been thoroughly elucidated. In this study, we report for the absence of PPO in Cynomorium coccineum, a holoparasitic plant adapted to withstand unfavorable climatic conditions, growing in Mediterranean countries and amply used in traditional medicine. The lack of PPO has been demonstrated by the absence of enzymatic activity with various substrates, by the lack of immunohistochemical detection of the enzyme, and by the absence of the PPO gene and, consequently, its expression. The results obtained in our work allow us to exclude the presence of the PPO activity (both latent and mature forms of the enzyme), as well as of one or more genes coding for PPO in C. coccineum. Finally, we discuss the possible significance of PPO deficiency in parasitic plants adapted to abiotic stress.

中文翻译：

---

广泛存在的全寄生植物锁阳锁阳中的多酚氧化酶的缺乏。

多酚氧化酶（PPO，EC 1.14.18.1）是一种几乎普遍存在的酶，广泛分布于生物体之间。尽管PPO分布广泛，但尚未完全阐明其在植物中的作用。在这项研究中，我们报告了锁阳锁阳中不含PPO，一种全寄生植物，适应恶劣的气候条件，在地中海国家生长，已广泛用于传统医学中。通过缺乏对各种底物的酶促活性，通过缺乏对该酶的免疫组织化学检测以及通过缺乏PPO基因及其表达来证明PPO的缺乏。在我们的工作中获得的结果使我们能够排除PPO活性（酶的潜伏形式和成熟形式）以及球菌中PPO编码的一种或多种基因的存在。最后，我们讨论了适应非生物胁迫的寄生植物中PPO缺乏的可能意义。