Purification and characterization of enzymes involved in the degradation of chemotactic N-formyl peptides.
Purification and characterization of enzymes involved in the degradation of chemotactic N-formyl peptides.
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参与趋化 N-甲酰肽降解的酶的纯化和表征。
DOI：
10.1021/bi050191o
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Pei,Dehua
中科院分区：
文献类型：
--
作者：
Nguyen,KietT;Pei,Dehua
N-甲酰肽来源于细菌和线粒体蛋白的蛋白水解降解/加工，并作为哺乳动物吞噬白细胞的有效化学引诱剂。对肠道细菌释放的趋化性N-甲酰肽的反应可能是有害的，导致不必要的炎症。在这里，两种酶，依次采取行动，降解N-甲酰肽纯化大鼠肠粘膜层和生化特征。第一种酶裂解趋化肽f-MLF释放N-甲酰甲硫氨酸（f-Met）和二肽亮氨酰苯丙氨酸，akcat值为14 s-1，aKM值为0.60 mM，akcat/KM值为22500 M-1 s-1。凝胶内胰蛋白酶消化后进行质谱指纹分析，将该蛋白鉴定为α-N-酰基肽水解酶（或酰基氨基酸释放酶，EC 3.4.19.1）。第二种酶水解N-甲酰甲硫氨酸为甲酸盐和甲硫氨酸，akcat值为7.9 s-1，aKM值为3.1 mM，akcat/Km值为2550 M-1 s-1。该蛋白被鉴定为N-酰化酶IA（或N α-酰基-1-氨基酸酰胺水解酶，EC 3.5.1.14）。这两种酶一起在降解细菌和线粒体N-甲酰化肽中起保护作用。
N-Formyl peptides are derived from proteolytic degradation/processing of bacterial and mitochondrial proteins and serve as potent chemoattractants for mammalian phagocytic leukocytes. A response to the chemotacticN-formyl peptides released by commensal bacteria in the gut region could be detrimental, leading to unwanted inflammation. Here, two enzymes that act sequentially to degradeN-formyl peptides were purified from the rat intestinal mucosal layer and biochemically characterized. The first enzyme cleaves chemotactic peptide f-MLF to releaseN-formylmethionine (f-Met) and dipeptide leucylphenylalanine, with akcatvalue of 14 s-1,aKMvalue of 0.60 mM, and akcat/KMvalue of 22 500 M-1s-1. In-gel tryptic digestion followed by mass spectral fingerprinting identified the protein as the α-N-acylpeptide hydrolase (or acylamino acid-releasing enzyme, EC 3.4.19.1). The second enzyme hydrolyzesN-formylmethionine into formate and methionine with akcatvalue of 7.9 s-1, aKMvalue of 3.1 mM, and akcat/KMvalue of 2550 M-1s-1. This protein was identified as theN-acylase IA (orNα-acyl-l-amino acid amidohydrolase, EC 3.5.1.14). Together, these two enzymes play a protective role in degrading bacterial and mitochondrial N-formylated peptides.