Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Biochemistry. 2009 Dec 22;48(50):11971-81. doi: 10.1021/bi901637c.
Prolyl endopeptidase (Prep) is a member of the prolyl peptidase family and is of interest because of its unique biochemistry and connections to cognitive function. Using an unbiased mass spectrometry (MS)-based peptidomics platform, we identified Prep-regulated peptides in the central nervous system (CNS) of mice by measuring changes in the peptidome as a function of Prep activity. This approach was validated by the identification of known Prep substrates, such as the neuropeptide substance P and thymosin-beta4, the precursor to the bioactive peptide Ac-SDKP. In addition to these known substrates, we also discovered that Prep regulates many additional peptides, including additional bioactive peptides and proline rich peptides (PRPs). Biochemical experiments confirmed that some of these Prep-regulated peptides are indeed substrates of the enzyme. Moreover, these experiments also supported the known preference of Prep for shorter peptides while revealing a previously unknown cleavage site specificity of Prep when processing certain multi-proline-containing peptides, including PRPs. The discovery of Prep-regulated peptides implicates Prep in new biological pathways and provides insights into the biochemistry of this enzyme.
脯氨酰内肽酶（Prep）是脯氨酰肽酶家族的成员，因其独特的生物化学特性和与认知功能的联系而备受关注。我们使用基于无偏质谱（MS）的肽组学平台，通过测量 Prep 活性变化对中枢神经系统（CNS）中肽组的影响，鉴定出 Prep 调节的肽。这种方法通过鉴定已知的 Prep 底物（如神经肽 P 和胸腺素-β4，生物活性肽 Ac-SDKP 的前体）得到了验证。除了这些已知的底物外，我们还发现 Prep 还调节许多其他肽，包括其他生物活性肽和富含脯氨酸的肽（PRPs）。生化实验证实，其中一些 Prep 调节的肽确实是该酶的底物。此外，这些实验还支持了 Prep 对较短肽的已知偏好，同时揭示了 Prep 在处理某些含有多个脯氨酸的肽时，包括 PRPs，的以前未知的切割位点特异性。Prep 调节肽的发现表明 Prep 参与了新的生物学途径，并为该酶的生物化学提供了深入了解。
