Matsui T, Nakayama H, Yoshida K, Shinmyo A
Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma-shi, 630-0101 Nara, Japan.
Appl Microbiol Biotechnol. 2003 Oct;62(5-6):517-22. doi: 10.1007/s00253-003-1273-z. Epub 2003 Jul 16.
Peroxidases (PRX, EC 1.11.1.7) are widely distributed across microorganisms, plants, and animals; and, in plants, they have been implicated in a variety of secondary metabolic reactions. In particular, horseradish (Armoracia rusticana) root represents the main source of commercial PRX production. The prxC1a gene, which encodes horseradish PRX (HRP) C, is expressed mainly in the roots and stems of the horseradish plant. HRP C1a protein is shown to be synthesized as a preprotein with both a N-terminal (NTPP) and a C-terminal propeptide (CTPP). These propeptides, which might be responsible for intracellular localization or secretion, are removed before or concomitant with production of the mature protein. We investigated the functional role of HRP C1a NTPP and CTPP in the determination of the vesicular transport route, using an analytical system of transgenically cultured tobacco cells (Nicotiana tabacum, BY2). Here, we report that NTPP and CTPP are necessary and sufficient for accurate localization of mature HRP C1a protein to vacuoles of the vesicular transport system. We also demonstrate that HRP C1a derived from a preprotein lacking CTPP is shunted into the secretory pathway.
过氧化物酶（PRX，EC 1.11.1.7）广泛分布于微生物、植物和动物中；在植物中，它们参与了多种次生代谢反应。特别是辣根（Armoracia rusticana）根是商业生产PRX的主要来源。编码辣根PRX（HRP）C的prxC1a基因主要在辣根植物的根和茎中表达。HRP C1a蛋白显示为以前体蛋白形式合成，具有N端前肽（NTPP）和C端前肽（CTPP）。这些前肽可能负责细胞内定位或分泌，在成熟蛋白产生之前或同时被去除。我们使用转基因培养的烟草细胞（Nicotiana tabacum，BY2）分析系统，研究了HRP C1a NTPP和CTPP在确定囊泡运输途径中的功能作用。在此，我们报告NTPP和CTPP对于成熟HRP C1a蛋白准确定位于囊泡运输系统的液泡是必要且充分的。我们还证明，缺乏CTPP的前体蛋白衍生的HRP C1a被分流到分泌途径中。
