Cloning of a cDNA encoding an ectoenzyme that degrades thyrotropin-releasing hormone.

Section: Multiple Alignments and L-rap Modeling Suggest That In M1 Amsupporting

confidence: 48%

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confidence: 99%

Homology Modeling and Site-directed Mutagenesis of Pyroglutamyl Peptidase II

Chávez‐Gutiérrez¹,

Matta‐Camacho²,

Osuna³

et al. 2006

“…: 353-1-608-1608; Fax: 353-1-677-2400; e-mail: kellyja@tcd.ie. 1 The abbreviations used are: TRH-DE, thyrotropin-releasing hormone-degrading ectoenzyme; TRH, thyrotropin-releasing hormone; Glp-His-ProNH 2 , L-pyroglutamyl-L-histidyl-L-prolineamide; Glp, pyroglutamic acid; CPHNA, N- [1-carboxy-2-phenylethyl]N-imidazole benzyl histidyl-␤-naphthylamide; TRHAMC, pyroglutamyl-histidyl-prolylamido-4-methyl coumarin; AMC, 7-amino-4-methyl coumarin; Fmoc, N-(9-fluorenyl)methyloxycarbonyl; tBu, t-butyl ether; Trt, triphenylmethyl; Pmc, 2,2,5,7,8-pentamethylchromane-6-sulfonyl; Boc, N-␣-t-butyloxycarbonyl; OtBu, t-butylester; HBTU, 2-(1H-benztriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate; HOBt, N-hydroxybenzotriazole; DIPEA, N,N-diisopropylethylamine; HPLC, high pressure liquid chromatography; DPP-IV, dipeptidyl peptidase IV; Thi, thienylalanine. All amino acids are in the L configuration unless otherwise stated.…”

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confidence: 99%

“…Thyrotropin-releasing hormone-degrading ectoenzyme (TRH-DE) 1 (EC 3.4.19.6) is a type II cell surface peptidase located on synaptosomal membranes in the central nervous system (1Ϫ4). TRH-DE catalyzes the hydrolysis of the Glp-His bond in thyrotropin-releasing hormone (TRH), a tripeptide with the amino acid sequence L-pyroglutamyl-L-histidyl-L-prolineamide (Glp-His-ProNH 2 ) (5Ϫ10).…”

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confidence: 99%

Kinetic Investigation of the Specificity of Porcine Brain Thyrotropin-releasing Hormone-degrading Ectoenzyme for Thyrotropin-releasing Hormone-like Peptides

Kelly¹,

Slator²,

Tipton³

et al. 2000

Evidence indicates that neuronally released thyrotropin-releasing hormone (TRH) is selectively inactivated by TRH-degrading ectoenzyme (TRH-DE) (EC 3.4.19.6). TRH-DE inhibitors may be used to enhance the therapeutic actions of TRH and to investigate the functions of TRH and TRH-DE in the central nervous system.Although TRH-DE appears to exhibit a high degree of specificity toward TRH, systematic specificity studies, which would facilitate inhibitor design, have not been previously conducted for this enzyme. In this paper we present the first description of TRH-DE specificity across a directed peptide library in which the histidyl (P 1 ) residue of TRH was replaced by a series of amino acids. Peptides were synthesized using standard solid phase chemistry. Kinetic parameters were measured either by continuous or discontinuous fluorometric assays or by quantitative high pressure liquid chromatography. The P 1 residue was found to influence significantly both the ability of the peptides to bind to TRH-DE, as measured by their K i values, and the ability of TRH-DE to catalyze their hydrolysis. Moderately bulky, uncharged P 1 residues were found to bind preferentially to TRH-DE. Results from this screen provide valuable information for the development of TRH-DE inhibitors and have led to the identification of two potent, reversible TRH-DE inhibitors, L-pyroglutamyl-L-asparaginyl-L-prolineamide (K i ‫؍‬ 17.5 M) and Glp-AsnPro-7-amido-4-methyl coumarin (K i ‫؍‬ 0.97 M). Thyrotropin-releasinghormone-degrading ectoenzyme (TRH-DE) 1 (EC 3.4.19.6) is a type II cell surface peptidase located on synaptosomal membranes in the central nervous system (1Ϫ4). TRH-DE catalyzes the hydrolysis of the Glp-His bond in thyrotropin-releasing hormone (TRH), a tripeptide with the amino acid sequence L-pyroglutamyl-L-histidyl-L-prolineamide (Glp-His-ProNH 2 ) (5Ϫ10). This enzyme is strategically placed to play a significant role in extracellular inactivation of TRH, and current evidence strongly indicates that TRH-DE is the principal enzyme responsible for terminating the actions of neuronally released TRH (11Ϫ14).Although first recognized as a hypothalamic regulatory hormone, TRH is now believed to function as a neurotransmitter and/or neuromodulator within the central nervous system (15, 16) where it displays a broad spectrum of stimulatory actions independent of its neuroendocrine functions (15Ϫ17). Based on its central nervous system effects, TRH has been found to have potential use in the treatment of brain and spinal injury (18,19) and several central nervous system disorders, including spinocerebellar degeneration, cognitive deficits, and spinal cord pain transmission (16,17). The mechanisms by which TRH improves these conditions are not fully elucidated but appear to involve the potentiation by TRH of other neurotransmitter systems. Despite its promise, the use of TRH as a therapeutic agent is critically undermined by its susceptibility to proteolytic degradation (20).Compounds that potently and selectively inhibit TRH-DE may be use...

“…Gluzincin aminopeptidases share the consensus HEXXH(X) 18 E zinc-binding motif essential for enzymatic activity (10). This growing family of mammalian zinccontaining aminopeptidase includes membrane-bound (P-LAP, aminopeptidase A, aminopeptidase N, and thyrotropin-releasing hormone degrading enzyme) (3,4,6,11,12), cytosolic (puromycin-sensitive aminopeptidase (PSA) and leukotriene A 4 hydrolase) (13,14), secretory (aminopeptidase B) (15), and ER resident (A-LAP/ERAP1) (9,16) proteins. Mutational analyses revealed that essential amino acid residues are well conserved among members of the family (17)(18)(19)(20).…”

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confidence: 99%

Human Leukocyte-derived Arginine Aminopeptidase

Tanioka

Hattori

Masuda

et al. 2003

177

In this study we report the cloning and characterization of a novel human aminopeptidase, which we designate leukocyte-derived arginine aminopeptidase (L-RAP). The sequence encodes a 960-amino acid protein with significant homology to placental leucine aminopeptidase and adipocyte-derived leucine aminopeptidase. The predicted L-RAP contains the HEXXH(X) 18 E zinc-binding motif, which is characteristic of the M1 family of zinc metallopeptidases. Phylogenetic analysis indicates that L-RAP forms a distinct subfamily with placental leucine aminopeptidase and adipocyte-derived leucine aminopeptidase in the M1 family. Immunocytochemical analysis indicates that L-RAP is located in the lumenal side of the endoplasmic reticulum. Among various synthetic substrates tested, L-RAP revealed a preference for arginine, establishing that the enzyme is a novel arginine aminopeptidase with restricted substrate specificity. In addition to natural hormones such as angiotensin III and kallidin, L-RAP cleaved various N-terminal extended precursors to major histocompatibility complex class I-presented antigenic peptides. Like other proteins involved in antigen presentation, L-RAP is induced by interferon-␥. These results indicate that L-RAP is a novel aminopeptidase that can trim the N-terminal extended precursors to antigenic peptides in the endoplasmic reticulum.