蛋白酪氨酸磷酸酶(protein tyrosine phosphatase)的功能是去除蛋白上磷酸化酪氨酸的磷脂基团。蛋白酪氨酸磷酸化是一个常见的翻译后修饰，能够产生新的用于蛋白相互作用以及调节细胞内分布的识别位点，能够影响蛋白的稳定性，也能够调控酶的活性。正因如此，维持一个合适的蛋白酪氨酸磷酸化程度对很多细胞功能都是至关重要的。酪氨酸专一的蛋白磷酸酶(PTPase; EC3.1.3.48)催化脱去酪氨酸上的磷脂基团，整个过程通过一个半胱氨酸-磷脂中间体达成。这些酶在信号转导通路（比如MAP激酶通路）及细胞周期控制中是很关键的调控原件，它们在控制细胞生长、繁殖、分化以及转化中也很重要。

Protein tyrosine phosphatases are a group of enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins. Protein tyrosine (pTyr) phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular localization, affect protein stability, and regulate enzyme activity. As a consequence, maintaining an appropriate level of protein tyrosine phosphorylation is essential for many cellular functions. Tyrosine-specific protein phosphatases (PTPase; EC3.1.3.48) catalyse the removal of a phosphate group attached to a tyrosine residue, using a cysteinyl-phosphate enzyme intermediate. These enzymes are key regulatory components in signal transduction pathways (such as the MAP kinase pathway) and cell cycle control, and are important in the control of cell growth, proliferation, differentiation, transformation, and synaptic plasticity.