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Atotech
Atotech is a specialty chemicals and electroplating technology brand owned by MKS, supplying plating chemistry and equipment for printed circuit boards, semiconductors, and decorative surface finishing. It formed in 1993.
Atotoztli
Atotoztli was a royal woman of Tenochtitlan, said to be the daughter of Moctezuma I and the mother of three later rulers, Axayácatl, Tizoc, and Ahuízotl.
Atovaquone
Atovaquone (Mepron, 566C80) is a hydroxynaphthoquinone antiprotozoal drug inhibiting the mitochondrial cytochrome bc1 complex; used for Pneumocystis pneumonia and, with proguanil, malaria treatment and prophylaxis.
ATP Challenger Tour
ATP Challenger Tour: the second-highest tier of men's professional tennis, below the ATP Tour, founded 1978. Five categories (Challenger 175 to 50), 32-draw events, record $28.5m prize money in 2025, over 200 events in 2024.
ATP Finals
ATP Finals (Nitto ATP Finals), men's tennis year-end championship since 1970; eight qualifiers in round-robin groups; Turin since 2021; Djokovic record seven titles; Sinner champion 2024.
ATP Flight School
ATP Flight School is a large American flight training company headquartered in Jacksonville Beach, Florida. Founded in 1984 in Atlanta, it operates 87 training centers nationwide.
ATP rankings
PIF ATP Rankings (formerly Pepperstone ATP Rankings): official men's tennis ranking since 23 August 1973, first No. 1 Ilie Nastase. Rolling 52-week points system from 4 Slams, 8 Masters 1000, and best other results, used for entry, seeding, and No. 1 recognition.
ATP study
ATP study (ATP Project, Asthma afTer Polypectomy), NCT02427503: a completed Spanish observational cohort study of 106 adults with persistent asthma and grade II-III nasal polyposis, measuring eosinophils, FEV1, FeNO, and asthma control for 12 months after endoscopic sinus surgery.
ATP Tour
ATP Tour: the men's professional tennis circuit run by the Association of Tennis Professionals (formed 1972). 2026 season: 59 tournaments in 29 countries plus Grand Slams; Masters 1000, ATP 500, ATP 250 tiers; Nitto ATP Finals in Italy.
ATP Tour records
ATP Tour records: statistical bests in men's tennis since 1973. Djokovic 428 weeks at No. 1 and 24 majors, Federer 237 consecutive weeks at No. 1, Nadal 912 straight top-10 weeks and 14 French Opens, Connors 109 titles and 1,274 wins.
ATP-binding cassette transporter
ATP-binding cassette (ABC) transporters: ubiquitous ATP-powered membrane proteins with two NBDs and two TMDs; 48 human genes in seven subfamilies ABCA–G, linked to cystic fibrosis, adrenoleukodystrophy, cholestasis, and multidrug resistance.
ATP-dependent Clp protease ATP-binding subunit ClpA
ClpA is the E. coli AAA+ Hsp100 ATP-binding subunit of the ClpAP protease, a double-ring hexameric unfoldase that translocates substrates into ClpP and independently remodels proteins such as RepA.
ATP-dependent DNA helicase RecG
ATP-dependent DNA helicase RecG (recG, RECG_ECOLI) is a monomeric E. coli SF2 helicase, 693 amino acids, 76 kDa, with a wedge domain; it drives Holliday junction branch migration, fork regression, and R-loop/D-loop unwinding in DNA repair and recombination.
ATP-dependent helicase/nuclease subunit A
ATP-dependent helicase/nuclease subunit A (AddA): motor subunit of the bacterial AddAB helicase-nuclease that resects DNA double-strand breaks; SF1A helicase plus RecB-type nuclease cleaving the 3′ strand, Chi-regulated, in Firmicutes such as B. subtilis.
ATP-dependent protease subunit HslV
HslV (ClpQ) is the 19-kDa threonine peptidase subunit of the HslVU (ClpQY) ATP-dependent protease of E. coli, a hexameric-ring, proteasome-related bacterial protease activated by the HslU ATPase and degrading SulA and sigma-32.
ATP-dependent RNA helicase SrmB
SrmB is one of five DEAD-box RNA helicases of Escherichia coli, discovered in 1988 as a suppressor of an L24 ribosomal protein mutation. It aids early 50S ribosomal subunit assembly, tethered via L4/L24 to 23S rRNA, with weak ATPase but strong ATP-independent RNA annealing activity.
ATP13A2
ATP13A2 (PARK9) is a lysosomal P5-type ATPase on chromosome 1p36 that exports polyamines such as spermine; biallelic mutations cause Kufor-Rakeb syndrome, CLN12 neuronal ceroid lipofuscinosis, and spastic paraplegia 78.
ATP1A1
ATP1A1 (ATPase Na+/K+ transporting subunit alpha 1) encodes the alpha-1 catalytic subunit of the human sodium-potassium pump, which exports 3 Na+ and imports 2 K+ per ATP; ubiquitous isoform linked to aldosteronism, neuropathy, and cardiotonic steroid sensitivity.
ATP1A2
ATP1A2 (FHM2, MHP2) is a human gene on chromosome 1q23.2 encoding the alpha 2 subunit of the Na+/K+-ATPase sodium pump, expressed mainly in astrocytes and skeletal muscle; mutations cause familial hemiplegic migraine type 2 and alternating hemiplegia of childhood.
ATP1A3
ATP1A3 (also DYT12, AHC2, RDP, CAPOS, DEE99), a gene at 19q13.2 encoding the neuronal alpha-3 subunit of the Na+/K+-ATPase sodium pump; heterozygous pathogenic variants cause alternating hemiplegia of childhood, rapid-onset dystonia-parkinsonism, and CAPOS syndrome.
ATP2A2
ATP2A2 (SERCA2 gene) on chromosome 12q24.11 encodes a calcium ATPase pump; isoforms SERCA2a/b/c; heterozygous mutations cause Darier disease, newer variants cause rhabdomyolysis and vacuolar myopathy.
ATP2B1
ATP2B1 (PMCA1), human gene at 12q21.3 encoding plasma membrane calcium-transporting ATPase 1, a P-type ATPase pumping Ca2+ out of cells; key hypertension GWAS locus, embryonic lethal when knocked out in mice.
ATP2B4
ATP2B4 (PMCA4, plasma membrane calcium-transporting ATPase 4) is a human gene at 1q32.1 encoding a P-type ATPase calcium pump; splice variants PMCA4a/4b, sperm motility, nNOS scaffolding, and malaria variant associations distinguish it.
ATP2C1
ATP2C1 (SPCA1, hSPCA1, PMR1) is a human gene on chromosome 3q22.1 encoding a Golgi P-type ATPase pump that transports one Ca2+ or Mn2+ ion per ATP; haploinsufficiency causes Hailey–Hailey disease.
ATP5F1A
ATP5F1A (ATP5A1) is a human gene on chromosome 18q21.1 encoding the alpha subunit of mitochondrial ATP synthase F1; dominant de novo missense variants cause developmental delay, dystonia, and complex V deficiency.
ATP6AP1-CDG
ATP6AP1-CDG (CDG-IIs, Immunodeficiency 47, OMIM 300972) is a rare X-linked recessive congenital disorder of glycosylation causing hepatopathy, immunodeficiency, cutis laxa, and type II transferrin glycosylation defects, first described in 2016.
ATP6AP2
ATP6AP2, also known as the (pro)renin receptor, is a human X-linked gene on chromosome Xp11.4 encoding a 350-amino-acid membrane protein essential to V-ATPase function and linked to intellectual disability.
ATP7A
ATP7A (MNK) is an X-linked gene encoding a copper-transporting P-type ATPase that supplies copper to secretory cuproenzymes and exports excess copper; mutations cause Menkes disease, occipital horn syndrome, and distal motor neuropathy.
ATPase
ATPase: enzymes hydrolyzing ATP; transport ATPases comprise P-type (phosphoenzyme pumps), rotary F-, V-, A-type ion-translocating ATP synthases, and ABC transporters, driving ion gradients, ATP synthesis, lipid flipping, and drug resistance.
ATPase assay
An ATPase assay is a biochemical measurement of ATP hydrolysis by ATPase enzymes, most commonly quantifying released inorganic phosphate, used to functionally characterize new ATPases and measure their turnover rates.