Isolation and Characterization of a Novel UV Photoreceptor P_<290>

从豌豆（PisumsativumL.）黄化的表皮中提取了UV-B光感受器的候选者。栽培变种Alaska and Progress No. 9）、蚕豆（Vicia faba L.）和高粱（Sorghum bicolor Moench）。根据紫外光谱、核磁共振和质谱等的研究结果，从阿拉斯加豌豆中提取的大豆皂甙的结构被提出为22-O-[3-羟基-2-甲基-4-吡喃酰基]-大豆皂甙I。由于除大豆皂苷I外，还存在紫外吸收部分3-羟基-2-甲基-4-吡喃酮，因此将其命名为色皂苷I。高粱中的一种不同，命名为色皂甙Ⅱ。用缓冲液从阿拉斯加豌豆中仔细提取，凝胶渗透色谱和凝胶电泳表明，在植物细胞中，它主要以约53千道尔顿的蛋白质缀合物形式存在。在豌豆植物中，它最丰富地发生在顶端钩和根尖，在那里细胞分化发生最活跃。无论是chromosaponin I蛋白质缀合物是生物学功能在这项研究中没有澄清，因为我们未能在诱导胡萝卜原生质体中的花色素苷合成，该蛋白质缀合物的抗体原本计划测试是否抑制UV-B的作用。现在我们正在尝试一种替代的体外转录系统，除了上述结果外，我们还获得了以下发现：1。UV-B光感受器与DNA或RNA不同，其作用光谱可放大光敏色素介导的高粱花色素苷合成，也可抑制UV-B和红光诱导的高粱花色素苷合成. UV-B诱导微小红酵母细胞壁和质膜成分发生快速变化。

Candidates of the UV-B photoreceptors were extracted from etiolated seedings of peas (Pisum sativum L. Cvs. Alaska and Progress No. 9), broad bean (Vicia faba L.) and sorghum (Sorghum bicolor Moench). Of the one from Alaska pea the structure was proposed as 22-O-[3-hydroxy-2-methyl-4-pyronyl]-soyaponin I, based on the findings of UV spectroscopy, nuclear magnetic resonance and mass spectrometries and others. Because of the presence of a UV-absorbing moiety, 3-hydroxy-2-methyl-4-pyrone, in addition to soyasaponin I, it was named chromosaponin I. The one from sorghum was different, and was named chromosaponin II. A careful extraction from Alaska pea with a buffer, gel permeation chromatography and gel-electrophoresis suggested that in plant cells it occurs mostly as a protein conjugate of about 53 kilodaltons. In a pea plant it occurs most abundantly in the apical hook and the root tip, where cell differentiation takes place most actively.Whether the chromosaponin I protein conjugate is biologically functional was not clarified in this study, because we failed in inducing anthocyanin synthesis in carrot protoplasts, on which the antibody of this protein conjugate had originally been planned to test whether or not it inhibits UV-B action. Now we are attempting an alternative to use an in vitro transcription system.In addition to the above-stated results we obtained the following findings :1. UV-B photoreceptor(s) is different from DNA or RNA, judging from action spectra for amplification of phytochrome-mediated anthocyanin synthesis and for inhibition of anthocyanin synthesis induced by UV-B and red light in sorghum.2. UV-B induces rapid changes in constituents of cell wall and plasma membrane of the yeast, Rhodotorula minuta.