Department of Biochemistry, University of Nevada, Reno, Nevada 89557-0014.
Plant Physiol. 1992 Aug;99(4):1546-50. doi: 10.1104/pp.99.4.1546.
2'-Carboxyarabinitol 1-phosphate (CA1P) is a naturally occurring inhibitor of ribulose-1,5 bisphosphate carboxylase/oxygenase activity. A chloroplast phosphatase has previously been identified that degrades CA1P in vitro to carboxyarabinitol (CA) plus phosphate, but CA has not yet been detected in plants. Here, we detail procedures to isolate and assay CA from leaves and utilize mass spectrometry to demonstrate for the first time that CA is present in plants. CA was present in leaves of all 13 species examined, including those of C(3), C(4), and Crassulacean acid metabolism photosynthetic subgroups. CA was present both in species with high levels of CA1P (e.g. Phaseolus vulgaris, Lycopersicon esculentum, Beta vulgaris) as well as in species with low levels of CA1P (e.g. Spinacea oleracea, Triticum aestivum). CA levels in the light were sometimes greater than those in the dark. Bean leaves had the most CA of any species tested, with levels in the light approaching 1 micromole per milligram of chlorophyll. In illuminated bean leaves, about 63% of the CA is located outside the chloroplast. CA is one of only a few branched chain sugar acids to be identified from plants.
2'-羧基阿拉伯糖醇 1-磷酸（CA1P）是一种天然存在的核酮糖-1,5-二磷酸羧化酶/加氧酶活性抑制剂。先前已经鉴定出一种叶绿体磷酸酶，它可在体外将 CA1P 降解为阿拉伯糖醇（CA）加磷酸盐，但 CA 尚未在植物中检测到。在这里，我们详细介绍了从叶片中分离和测定 CA 的程序，并利用质谱首次证明 CA 存在于植物中。CA 存在于 13 种被检测物种的叶片中，包括 C（3）、C（4）和景天酸代谢光合亚群的物种。CA 存在于 CA1P 水平高的物种（例如菜豆、番茄、蕹菜）和 CA1P 水平低的物种（例如菠菜、小麦）中。在光下 CA 的含量有时高于在黑暗中。豆科植物的叶片中 CA 含量最高，在光下的含量接近每毫克叶绿素 1 微摩尔。在受照的豆科植物叶片中，约 63%的 CA 位于叶绿体之外。CA 是仅从植物中鉴定出的几种支链糖酸之一。
