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Enzymatic Degradation of Bradykinin
Published in Sami I. Said, Proinflammatory and Antiinflammatory Peptides, 2020
Randal A. Skidgel, Ervin G. Erdös
Aminopeptidases remove amino acids sequentially from the N terminus of peptides and proteins. Bk contains a Pro2 that makes it resistant to most aminopeptidases, but the aminopeptidase P cleaves peptides with a proline in the second position; consequently, it can inactivate Bk at the Arg1-Pro2 bond.
Protein and amino acids
Published in Geoffrey P. Webb, Nutrition, 2019
The following peptidases break off one of the amino acids at the end of the peptide chain and these are termed exopeptidases. Carboxypeptidases in pancreatic juice break off the C-terminal amino acid. Aminopeptidases located on the surface of the small intestine break off the N-terminal amino acid.
Peptidases and Neuropeptide-Inactivating Mechanisms in the Circulation and in the Gastrointestinal Tract
Published in Edwin E. Daniel, Neuropeptide Function in the Gastrointestinal Tract, 2019
Table 5 illustrates the distribution of the peptidases that were either detected or purified from seven organs of the gastrointestinal tract. From a qualitative point of view, most of these organs exhibit a rich peptidasic content. Aminopeptidase B was detected fluorimetrically in all organs of the rat gastrointestinal tract56 as well as in the porcine jejunum.57 In the rat, this peptidase appeared to be abundant in the small intestine (duodenum, jejunum, and ileum), with a specific activity (Vmax≃ 556 nmol of 7AMC released per hour per milligram of protein) that was three- to fivefold higher than in the other organs.56 Interestingly, the distribution of this enzyme paralleled that observed for aminopeptidase N, which was detected in high amounts in the rat small intestine,56 while it was present in 20- to 30- fold lower amounts in the other organs.56 These data corroborated previous studies showing that the highest level of specific activity of this enzyme was recovered in the distal part of the ileum.58 Furthermore, immunohistochemical localization of aminopeptidase M had revealed that the peptidase was mainly present in the rat small gut, with stain particularly concentrated at the entire luminal surface.59
Lack of Associations between Endoplasmic Reticulum Aminopeptidase 2 Gene Polymorphisms and Ankylosing Spondylitis: A Meta-analysis with Trial Sequential Analysis
Published in Immunological Investigations, 2022
Shutao Gao, Tao Xu, Chao Mao, Jie Cheng, Chuanhui Xun, Weidong Liang, Weibin Sheng
The ERAP1 and ERAP2 aminopeptidases are intracellular enzymes encoded by ERAP1 and ERAP2, which are neighboring genes structured in an opposite orientation on chromosome 5q15. The protein sequences of ERAP2 and ERAP1 are 49% identical (Brown et al. 2016). Despite substantial work that has been done, the precise mechanism by which aminopeptidases influence AS is still largely undefined. Both of the two aminopeptidases serve as molecular rulers in trimming peptides to suitable lengths before presentation by HLA-I molecules. ERAP2 may act in concert with ERAP1, and dimerization of ERAP1-ERAP2 considerably increases peptide-trimming efficiency (Evnouchidou et al. 2014; Lorente et al. 2013). Chen et al. reported that the ERAP1/ERAP2 heterodimer could work as a peptide editor by trimming substrates into optimal sizes, thus allowing the MHC-I groove to reach a closed conformation (Chen et al. 2016). Besides, ERAP2 can mediate the expression and activity of ERAP1, as well as modify the peptidome (Paladini et al. 2019a).
Recent advances in proteolytic stability for peptide, protein, and antibody drug discovery
Published in Expert Opinion on Drug Discovery, 2021
Xianyin Lai, Jason Tang, Mohamed E.H. ElSayed
In contrast to carboxypeptidases, aminopeptidases cleave peptide bonds at the N-terminus of proteins. They are widely distributed in many organs and found in many subcellular organelles, cytoplasms, and as membrane components. Aminopeptidases are classified by multiple criteria. Depending on the number of amino acids cleaved from the N-terminus, enzymes that remove one NH2-terminal amino acid are called aminopeptidases, enzymes that remove two NH2-terminal amino acids are called dipeptidyl peptidases, and enzymes that remove three NH2-terminal amino acids are called tripeptidyl peptidases. Based on which residues are removed, aminopeptidases are classified as alanyl, arginyl, aspartyl, cystinyl, leucyl, glutamyl, and methionyl aminopeptidase. Other factors, such as location, pH, susceptibility to inhibition, metal ion content, etc. are applied to category aminopeptidases [69].
Association study of polymorphisms of endoplasmic reticulum aminopeptidase 1 gene with preeclampsia in Chinese populations
Published in Clinical and Experimental Hypertension, 2021
Cui Ma, Yuanyuan Zheng, Xiaowei Liu, Weiyuan Zhang
Johnson MP et al. (14) found that rs3734016 for ERAP-1 and rs2549782 for ERAP-2 were associated with the incidence of preeclampsia in the Australian population when analyzing the correlation between several SNPs of ERAP gene and preeclampsia. RS34750 for ERAP-1and RS17408150 for ERAP-2 were associated with preeclampsia in the Norwegian population. Hill LD et al. (15) found a significant association between the fetal rs2549782 and preeclampsia in the African-American population (P = .009), and showed increased ERAP-2 transcription in decidua tissues of PE patients. However, the expression level of ERAP-2 protein was not analyzed in this study. These evidences suggested related variants of ERAP genes were associated with preeclampsia. However, the mechanisms of ERAP affecting the occurrence of diseases were unclear. In addition, studies have shown that gene polymorphisms that increase the activity of aminopeptidase were likely to cause immune diseases, and the increased risk is attributed to the increased protein expression levels of ERAP-1 and ERAP-2 (16). Studies have shown that the abnormal elevation of ERAP-1 in placental tissues was closely related to preeclampsia, which may participate in the occurrence of preeclampsia through immune imbalance, promotion of inflammation, and inhibition of angiogenesis. The results showed that the expression levels of mRNA and protein of ERAP-1 in the PE group were higher than those in the normal maternal group, which might also be caused by the ERAP-1 related variant genes, which could be verified by genome-wide association analysis (GWAS) later (17).