Ditlecadet Delphine, Driedzic William R
Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada,
Fish Physiol Biochem. 2014 Feb;40(1):257-66. doi: 10.1007/s10695-013-9841-3. Epub 2013 Aug 8.
Rainbow smelt (Osmerus mordax) synthesize high amounts of glycerol in winter as a cryoprotectant through the direct dephosphorylation of glycerol-3-phosphate by a phosphatase, glycerol-3-phosphatase (G3Pase). Such a protein is well described in a few species including fungi, bacteria and plants but never studied beyond tissue homogenates in any animal species. Purification, identification and characterization of this enzyme is thus crucial for a better comprehension of the biochemical adaptation in rainbow smelt in response to low temperature and more generally of the biochemical mechanisms involved in glycerol synthesis in animals. This work presents the first attempt to purify G3Pase from smelt liver, the main site of glycerol synthesis for the whole animal. A partial purification was performed, and some characteristics of the protein determined, including optimal pH, K(m) and cation requirements. Smelt G3Pase is most likely a low molecular weight, Mg⁺-dependent and cytosolic phosphatase.
彩虹香鱼（Osmerus mordax）在冬季通过磷酸酶甘油-3-磷酸酶（G3Pase）将甘油-3-磷酸直接去磷酸化，从而合成大量甘油作为抗冻剂。这种蛋白质在包括真菌、细菌和植物在内的少数物种中已有详细描述，但在任何动物物种中，除了组织匀浆外，从未进行过深入研究。因此，对这种酶进行纯化、鉴定和表征，对于更好地理解彩虹香鱼对低温的生化适应性，以及更广泛地理解动物体内甘油合成所涉及的生化机制至关重要。这项工作首次尝试从香鱼肝中纯化G3Pase，香鱼肝是整个动物甘油合成的主要部位。进行了部分纯化，并测定了该蛋白质的一些特性，包括最佳pH值、米氏常数（K(m)）和阳离子需求。香鱼G3Pase很可能是一种低分子量、依赖Mg⁺的胞质磷酸酶。
