Amphibian metamorphosis is a tightly regulated transformation involving the participation of hormones and other biomolecules in cell death and tail absorption. Among the regulators, phosphate is essential for various processes, such as cell death and survival and enzyme activity regulation. Therefore, identification and characterization of phosphatases in L. catesbeianus tail may contribute to understand the events involved in cell death and nutrient release during metamorphosis. Differential centrifugation was used to separate soluble proteins from membrane proteins and analyzed by phosphomonohydrolases, serine/threonine protein phosphatase 2A (PP2A), and protein tyrosine phosphatase (PTP) assays. Mitochondrial fractioning was used to evaluate PP2A and alkaline phosphatase activities. Tandem mass spectrometry (MS/MS) analysis was performed using the crude extract. Phosphomonohydrolase activity was assayed by p-nitrophenylphosphate (pNPP) hydrolysis, whereas PP2A and PTP were assayed by peptides phosphorylated in threonine and tyrosine, respectively; inhibitor-2 was used to identify the serine/threonine protein phosphatase type 1 (PP1). The enzymatic activities and kinetic parameters of pNPP hydrolysis revealed three distinct phosphomonohydrolases. MS/MS analysis of the crude extract revealed three protein phosphatases, viz., PP2A, PP1, and a PTP, which was confirmed by in vitro assays. The results may relate PP2A activity to membrane-bound alkaline phosphatase, PTP activity to soluble acid phosphatase, and PP1 activity to membrane acid phosphatase, although more detailed studies are needed to confirm this hypothesis. We propose a model providing information on the role of PP1 and PP2A in the signaling events leading to cell death and the role of these enzymes in anuran tail absorption during metamorphosis.

两栖动物变态是一种严格调控的转化，涉及激素和其他生物分子参与细胞死亡和尾部吸收。在调节剂中，磷酸盐对各种过程至关重要，例如细胞死亡和存活以及酶活性调节。因此，L. catesbeianus中磷酸酶的鉴定和表征tail 可能有助于了解在变态过程中涉及细胞死亡和养分释放的事件。差速离心用于从膜蛋白中分离可溶性蛋白，并通过磷酸单水解酶、丝氨酸/苏氨酸蛋白磷酸酶 2A (PP2A) 和蛋白酪氨酸磷酸酶 (PTP) 分析进行分析。线粒体分级用于评估 PP2A 和碱性磷酸酶活性。使用粗提取物进行串联质谱 (MS/MS) 分析。磷酸单糖水解酶活性通过对硝基苯磷酸（pNPP) 水解，而 PP2A 和 PTP 分别通过在苏氨酸和酪氨酸中磷酸化的肽进行测定；抑制剂 2 用于鉴定丝氨酸/苏氨酸蛋白磷酸酶 1 型 (PP1)。p的酶活性和动力学参数NPP 水解揭示了三种不同的磷酸单水解酶。粗提物的 MS/MS 分析揭示了三种蛋白磷酸酶，即 PP2A、PP1 和 PTP，这已通过体外分析得到证实。结果可能将 PP2A 活性与膜结合碱性磷酸酶相关，PTP 活性与可溶性酸性磷酸酶相关，PP1 活性与膜酸性磷酸酶相关，尽管需要更详细的研究来证实这一假设。我们提出了一个模型，该模型提供了关于 PP1 和 PP2A 在导致细胞死亡的信号事件中的作用以及这些酶在变态过程中无尾尾吸收中的作用的信息。