All articles starting with P
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Peptic ulcer disease
Peptic ulcer disease (PUD), also called gastric or duodenal ulcer, is a sore in the stomach or duodenal lining caused mainly by Helicobacter pylori infection or NSAIDs; antibiotics cure most cases.
Peptidase 1 (mite)
Peptidase 1 (mite), or Der p 1, is the major papain-like cysteine protease allergen of Dermatophagoides pteronyssinus feces; over 80% of house dust mite-allergic patients are sensitized, and it anchors diagnosis, exposure measurement, and immunotherapy dosing.
Peptidase A31, hydrogenase expression/formation protein
Peptidase family A31 (HybD endopeptidase family; hupD, hycI, hoxW, hupW) comprises aspartic-type endopeptidases that cleave the C-terminus of [NiFe] hydrogenase large subunits after nickel insertion, the final maturation step.
Peptidase A5, thermopsin
Thermopsin, EC 3.4.23.42, is a thermostable acid endopeptidase secreted by the thermoacidophilic archaeon Sulfolobus acidocaldarius, most active at pH 2, and the type example of peptidase family A5.
Peptidase C13, legumain
Peptidase family C13 (legumain family, MEROPS) contains asparaginyl endopeptidases such as mammalian legumain/AEP/δ-secretase and GPI:protein transamidase; clan CD cysteine proteases cleaving after Asn, pH-dependent, with ligase activity.
Peptidase C19, ubiquitin-specific peptidase, DUSP domain
DUSP domain (IPR006615), a ~120-residue auxiliary domain present in ubiquitin-specific proteases (peptidase C19) such as USP4, USP11, USP15, USP20, and USP33; tripod-like fold with PGPI motif, regulating catalysis and substrate binding.
Peptidase C1B, bleomycin hydrolase
Peptidase C1B, bleomycin hydrolase (EC 3.4.22.40, BLMH) is a papain-like cysteine peptidase subfamily whose hexameric eukaryotic members detoxify the anticancer drug bleomycin by deamidation, driving bleomycin resistance, while bacterial members are aminopeptidases C.
Peptidase M12A
Peptidase M12A, the astacin subfamily of MEROPS family M12, comprises zinc-dependent metzincin metalloendopeptidases named for crayfish astacin, with HEXXHXXGXXH catalysis, six human genes, and roles in digestion, development, and hatching.
Peptidase M17, peptidase B
Peptidase M17 (leucyl aminopeptidase, peptidase B, EC 3.4.11.1) is a hexameric zinc-dependent aminopeptidase family with a binuclear metal center that cleaves N-terminal leucine-like residues; a validated antimalarial and antibacterial drug target.
Peptidase M3B, oligoendopeptidase F
Oligoendopeptidase F (PepF), MEROPS M03.007, is a zinc-dependent bacterial metallopeptidase from Lactococcus lactis that cleaves 7-17 residue peptides after Phe, with roles in protein secretion and sporulation.
Peptidase S13, D-Ala-D-Ala carboxypeptidase C
Peptidase S13 (D-Ala-D-Ala carboxypeptidase C family) is a MEROPS serine peptidase family of bacterial penicillin-binding proteins, including E. coli PBP4, that cleave D-Ala-D-Ala bonds in peptidoglycan and are inhibited by beta-lactams.
Peptidase S1A, nudel
Peptidase S1A, nudel (InterPro IPR015420; MEROPS S01.013) is the protein family of the nudel-type serine protease domain, exemplified by Drosophila Nudel, a 2616-amino-acid maternal protein required for Toll-activating dorsoventral patterning and vitelline membrane cross-linking.
Peptidase S48, DNA-binding transcriptional activator HetR
HetR, classified in protein databases as the serine protease Peptidase S48, is a 299-amino-acid DNA-binding transcriptional activator of filamentous cyanobacteria that acts as master regulator of heterocyst differentiation, identified in Anabaena sp. PCC 7120 in 1991.
Peptide
Peptides: short amino-acid chains acting as hormones, neurotransmitters, and drugs (insulin, 1922; 500-5000 Da therapeutics). Covers signaling biology, peptide drug applications, 2026 FDA compounding votes, and gray-market quality concerns.
Peptide amphiphiles
Peptide amphiphiles are molecules with a hydrophobic alkyl tail and a hydrophilic peptide head that self-assemble in water into nanofibers, used as scaffolds for tissue regeneration and drug delivery.
Peptide bond
The peptide bond, or peptide linkage, is the amide covalent bond linking amino acids into polypeptide chains, formed by loss of a water molecule and made rigid and planar by resonance.
Peptide C–H functionalization
Peptide C–H functionalization directly converts carbon–hydrogen bonds within amino acid residues of a peptide into carbon–carbon or carbon–heteroatom bonds, bypassing prefunctionalized groups and enabling late-stage modification such as macrocyclization and stapling of peptide therapeutics.
Peptide chain elongation
Peptide chain elongation: the translation stage in which ribosomes decode mRNA codons, form peptide bonds, and translocate, using eEF1A, eEF2, and eIF5A at 3–5 amino acids per second; a major antibiotic target.
Peptide chain release factor
Peptide chain release factors (RF1, RF2, RF3 in bacteria; eRF1, eRF3 in eukaryotes) are proteins that recognize stop codons and hydrolyze peptidyl-tRNA to terminate translation, with unrelated bacterial and archaeo-eukaryotic lineages.
Peptide deformylase
Peptide deformylase (PDF, EC 3.5.1.31) is a bacterial metalloenzyme that removes the N-formyl group from N-terminal methionine after translation, and a target whose inhibitors reached clinical trials but saw no clinical use.
Peptide hormone
Peptide hormone: amino-acid-chain hormones (insulin, GLP-1s, secretin, oxytocin) acting via cell-surface receptors; made as preprohormones, short half-life, distinct from steroid hormones; basis of approved drugs and unapproved wellness peptides.
Peptide hydrogel
A peptide hydrogel is a water-rich, solid-like material where short peptides self-assemble through non-covalent interactions into nanofiber networks holding over 95% water, used as 3D cell culture scaffolds.
Peptide macrocyclization
Peptide macrocyclization is the chemical, enzymatic, or supramolecular ring-closing of a linear peptide into a macrocycle of 12 or more atoms, improving stability and binding.
Peptide mapping
Peptide mapping is an analytical biochemistry method that digests a protein with a protease and separates the peptides, giving a reproducible fingerprint used to confirm protein identity.
Peptide mass fingerprinting
Peptide mass fingerprinting (PMF) identifies an unknown protein by digesting it into peptides, measuring their masses by mass spectrometry, and matching them against a database.
Peptide methionine sulphoxide reductase MsrA domain
Peptide methionine sulphoxide reductase MsrA domain (IPR002569): catalytic domain of MsrA, EC 1.8.4.6, the S-epimer-specific methionine sulfoxide reductase with a GCFW motif and sulfenic acid mechanism, distinct from MsrB.
Peptide nanofibers
Peptide nanofibers are filaments with nanometer-scale diameters formed when short peptide molecules self-assemble in water, and they are engineered as biomaterials for drug delivery, vaccine carriers, and tissue repair.
Peptide receptor radionuclide therapy
Peptide receptor radionuclide therapy, or PRRT therapy, is a targeted radiopharmaceutical treatment in which lutetium-177 dotatate binds somatostatin receptors on neuroendocrine tumors and delivers beta radiation, approved in the US in 2018.
Peptide synthesis
Peptide synthesis is the laboratory construction of short amino acid chains, most commonly by solid-phase peptide synthesis on a polymer resin, a method introduced by R. B. Merrifield in 1963.
Peptide YY
Peptide YY (PYY) is a 36-amino-acid gut hormone released after meals; its circulating fragment PYY3-36 reduces appetite and food intake, and it was studied as an anti-obesity drug.