All articles starting with P

Peroxiredoxin

Peroxiredoxins (Prxs, Prdx): ubiquitous cysteine-based peroxidase enzymes reducing H2O2 and organic hydroperoxides via a peroxidatic cysteine, in typical 2-Cys, atypical 2-Cys, and 1-Cys classes, regulated by sulfiredoxin-reversible hyperoxidation.

Peroxisomal ABCD transporters

Peroxisomal ABCD transporters are three ATP-binding cassette half-transporters, ABCD1, ABCD2, and ABCD3, that import very-long-chain and branched-chain fatty acyl-CoA esters into peroxisomes; ABCD1 defects cause X-linked adrenoleukodystrophy.

Peroxisomal acyl-CoA oxidase deficiency

Peroxisomal acyl-CoA oxidase deficiency, also called pseudo-neonatal adrenoleukodystrophy (pseudo-NALD), is a rare autosomal recessive ACOX1 (17q25.1) disorder of peroxisomal VLCFA beta-oxidation causing neonatal hypotonia, seizures, and regression, distinct from Mitchell syndrome (dominant ACOX1 gain-of-function).

Peroxisomal Beta-Oxidation Enzymes

Peroxisomal beta-oxidation enzymes: peroxisomal acyl-CoA oxidases (ACOX1, ACOX2), multifunctional proteins (MFP-1/EHHADH, MFP-2/HSD17B4), and thiolases (ACAA1, SCPx) that shorten very long chain and branched fatty acids, producing H2O2, distinct from the mitochondrial system.

Peroxisomal LYS1 stabilizing protein 1

Pls1 (Ynl097c-b), Peroxisomal Lys1 Stabilizing protein 1, is a 40-amino-acid de novo yeast peroxisomal matrix protein that stabilizes Lys1 saccharopine dehydrogenase upon lysine deprivation, regulating lysine biosynthesis; unrelated to human PLS1 plastin.

Peroxisomal protein import

Peroxisomal protein import: post-translational delivery of folded matrix proteins into peroxisomes via PEX5/PEX7 receptors, a PEX13/PEX14 pore, PEX5 monoubiquitination, and PEX1/PEX6 ATP-driven recycling; defects cause Zellweger spectrum disorders.

Peroxisomal targeting signal 2 receptor

Peroxisomal targeting signal 2 receptor (peroxin-7, PTS2R), encoded by PEX7 at 6q23.3, imports PTS2-tagged enzymes AGPS, PHYH, and ACAA1 into peroxisomes with PEX5L; defects cause RCDP1 and some Refsum disease.

Peroxisome

Peroxisome: single-membrane eukaryotic organelle, no DNA, named by de Duve 1965; contains catalase and H2O2-producing oxidases; performs fatty acid alpha/beta-oxidation, plasmalogen synthesis; PEX gene defects cause Zellweger spectrum disorders.

Peroxisome proliferator-activated receptor

Peroxisome proliferator-activated receptors (PPARs): PPARα, PPARβ/δ, PPARγ, ligand-activated nuclear receptors cloned by Issemann and Green in 1990, heterodimerizing with RXR to regulate lipid and glucose metabolism; targets of fibrates and thiazolidinediones.

Peroxisome proliferator-activated receptor alpha

Peroxisome proliferator-activated receptor alpha (PPARα, NR1C1, PPARA) is a fatty acid-sensing nuclear receptor regulating lipid catabolism; target of fibrates, with PROMINENT trial failure and rodent-specific peroxisome proliferation.

Peroxisome proliferator-activated receptor gamma

PPARγ (PPARG, NR1C3) is a nuclear receptor and master regulator of adipocyte differentiation and insulin sensitivity; thiazolidinedione diabetes drugs target it, and dominant-negative PPARG mutations cause FPLD3 lipodystrophy.

Peroxymonosulfate

Peroxymonosulfate is an inorganic sulfur oxoanion with formula O5S2−, containing a peroxide bond, best known in potassium salts sold as Oxone and used as an oxidant.

Sep 29, 2026

Peroxymonosulfate oxidation

Peroxymonosulfate oxidation is an advanced oxidation process that degrades organic pollutants in water by activating peroxymonosulfate to generate sulfate radicals, an approach introduced for remediation in the late 1990s.

Peroxynitrite

Peroxynitrite (ONOO⁻) is a short-lived, reactive biological oxidant formed by the rapid reaction of nitric oxide with superoxide, and it induces cell death in vascular disease, inflammation, and neurodegeneration.

Sep 23, 2026

Peroz I

Peroz I (پیروز یکم) was the Sasanian King of Kings of Iran from 459 to 484, who took the throne from his brother Hormizd III in a civil war.

Perp walk

Perp walk: the American law enforcement practice of parading a handcuffed suspect before news cameras, also called perpetrator walk. Key facts: Fourth Amendment limits from Lauro v. Charles (2000), DOJ policy prohibition, and 2018 survey showing under one third public support.

Perpendicular

Perpendicular describes two lines, segments, rays, vectors, or planes that meet at a right angle of 90 degrees; in vector terms, perpendicular vectors have a dot product of zero.

Perpendicular magnetic anisotropy

Perpendicular magnetic anisotropy (PMA) is a magnetic property in which a thin film's easy axis points out of the film plane, underpinning perpendicular recording in hard disk drives and MRAM.

Perpendicular magnetic recording

Perpendicular magnetic recording (PMR) is a hard disk drive technology, proposed by Shunichi Iwasaki in 1975, that stores bits perpendicular to the disk surface for higher density.

Oct 22, 2026

Perpendicular magnetic tunnel junction

A perpendicular magnetic tunnel junction (pMTJ) is a magnetic tunnel junction whose two ferromagnetic layers magnetize out of the film plane, enabled by perpendicular magnetic anisotropy.

Oct 20, 2026

Perperakion

Perperakion (Hyperperakion; modern Perperikon), ancient Thracian city on a high hill in the eastern Rhodope mountains near Kardzhali, Bulgaria; Barrington Atlas 51 E1 settlement and mine, occupied from the 6th millennium BC to 1362.

Perpetrator trauma

Perpetrator trauma, also called perpetration-induced traumatic stress (PITS), is trauma arising from committing a wrong, first described among Vietnam War veterans in the 1970s.

Perpetua and Felicity

Perpetua and Felicity (Felicitas) were young Carthaginian Christian martyrs executed at Carthage on 7 March 203 CE; Perpetua's prison diary in the Passion is among the earliest surviving Christian women's writings.

Oct 22, 2026

Perpetua and the Habit of Unhappiness

Perpetua and the Habit of Unhappiness (Perpétue et l'habitude du malheur) is a 1974 novel by the Cameroonian writer Mongo Beti, published by Buchet/Chastel in Paris.

Perpetua Resources

Perpetua Resources Corp., formerly Midas Gold until its 2021 renaming, is a mining company advancing the Stibnite Gold Project, a gold and antimony mine in central Idaho.

Perpetual calendar

A perpetual calendar is a table, mechanical instrument, or calculation method, such as Conway's Doomsday rule, that works for many years because the Gregorian calendar repeats every 400 years.

Perpetual foreigner

The perpetual foreigner (forever foreigner) stereotype casts Asian Americans as inherently foreign regardless of citizenship or generations in the U.S.; a component of Kim's 1999 racial triangulation, distinct from the model minority stereotype.

Perpetual license

A perpetual license is a software license purchased for a one-time fee granting permanent usage rights to a fixed version, in contrast to a subscription that ends when the paid term expires.

Perpetual motion

Perpetual motion, also known as a perpetual motion machine or free energy device, is the hypothetical operation of a machine indefinitely without energy input, impossible under the laws of thermodynamics.