All articles A–Z

Amino acid activation

Amino acid activation: ATP-dependent two-step reaction by aminoacyl-tRNA synthetases forming an aminoacyl-adenylate, then charging tRNA's 3' end with a high-energy ester bond for translation.

Amino acid analysis is the chemical detection and quantification of free or total amino acids in a sample, using chromatographic separation followed by colorimetric, fluorescent, or mass-spectrometric detection.

Amino Acid conjugation

Amino acid conjugation (Reactome R-HSA-156587) is a phase II xenobiotic metabolism pathway: carboxylic-acid xenobiotics couple with glycine, taurine, or glutamine, and hydroxylamines with proline or serine, forming amide conjugates for elimination.

Amino acid N-carboxyanhydride

An amino acid N-carboxyanhydride, also called a Leuchs anhydride, is a five-membered cyclic anhydride of an α-amino acid, first synthesized by Hermann Leuchs in 1906.

Amino Acid Sequence

Amino acid sequence: the ordered linear arrangement of amino acid residues in a protein, equivalent to primary structure. First determined for insulin by Sanger in 1951; read today by Edman degradation and tandem mass spectrometry.

Amino acid synthesis

Amino acid synthesis: enzymatic pathways building the 22 translation amino acids from glycolysis, PPP, and TCA intermediates; nine are essential for humans; industrial fermentation uses C. glutamicum and E. coli.

Amino acid transporter

Amino acid transporter: membrane protein, mainly SLC families (SLC1, 3, 6, 7, 38, 43), moving amino acids by uniport, Na+- or H+-coupled symport, or exchange; linked to cystinuria and drug absorption.

Amino acid:DNA transferase

Amino acid:DNA transferase (ADDT, Pfam PF18724, InterPro IPR040741) is a phage enzyme domain transferring glycine, putrescine, or serine to 5-PmdU DNA, producing Nα-GlyT, Nα-PutT, or O-SerT hypermodifications that protect viral genomes from host restriction-modification defense.

Amino acids

Amino Acids (ISSN 0939-4451, eISSN 1438-2199) is a monthly peer-reviewed open-access Springer journal, founded 1991 in Austria, covering amino acid, peptide, and protein research; JIF 3.2 (2025).

Oct 20, 2026

Amino acids: mix

Amino acids: mix, EU active substance ID 334, a mixture of amino acids considered as a pesticide active substance; not approved in the EU, no CAS number, default MRL 0.01 mg/kg. Related amino acid blends serve as foliar biostimulants.

Aminoacidopathies

Aminoacidopathies are inherited disorders in which a defective enzyme or transport system blocks an amino acid's metabolism, letting it accumulate to toxic levels; phenylketonuria is the classic example.

Aminoaciduria

Aminoaciduria: excess amino acids in urine from overproduction or failed renal tubular reabsorption (ICD-11 GB90.47). Seen in Fanconi syndrome, cystinuria, Hartnup disease, lysinuric protein intolerance; over 99% of filtered amino acids are normally reabsorbed.

Aminoacyl tRNA synthetase

Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that charge tRNAs with amino acids in a two-step ATP-dependent reaction. Two unrelated classes (I Rossmann fold, II antiparallel beta-sheet) cover the 20 amino acids, with editing domains ensuring fidelity and moonlighting roles in disease.

Aminoacyl-tRNA

Aminoacyl-tRNA (charged tRNA): a transfer RNA ester-linked to its matching amino acid at the 3' end, made by aminoacyl-tRNA synthetases in a two-step ATP reaction, class I charging 2'-OH and class II 3'-OH, with editing for fidelity.

Aminoacylase 1 deficiency

Aminoacylase 1 deficiency (ACY1D, OMIM 609924) is a rare autosomal recessive inborn error of metabolism caused by ACY1 gene mutations, marked by urinary N-acetylated amino acids and variable neurological symptoms, from seizures to asymptomatic.

Aminobenzylamine

Aminobenzylamine is an aryl diamine, C₇H₁₀N₂, with one aromatic and one benzylic amine, occurring as three isomers and used as an epoxy curing agent and intermediate for polyamides, polyimides, pharmaceuticals, and pesticides.

Aminocaproic acid

Aminocaproic acid (EACA, Amicar), a synthetic lysine-analog antifibrinolytic, competitively blocks plasminogen activation to control bleeding; first described 1957 in Japan, FDA approved 1964, used in cardiac surgery blood conservation.

Aminodeoxychorismate synthase, component I

Aminodeoxychorismate synthase component I (PabB, pabB gene) is the chorismate-binding aminotransferase subunit of EC 2.6.1.85, which with PabA converts chorismate and glutamine to 4-amino-4-deoxychorismate for PABA and folate biosynthesis; distinct from anthranilate synthase TrpE.

Aminoethylethanolamine

Aminoethylethanolamine, or AEEA, is a colorless, viscous, water-miscible organic compound produced at industrial scale as a chemical intermediate for surfactants, epoxy curing agents, chelating agents, and corrosion inhibitors.

Aminoglutethimide

Aminoglutethimide, brand name Cytadren, is a drug derived from glutethimide that blocks steroid synthesis and was the first aromatase inhibitor used to treat advanced breast cancer.

Aminoglycoside

Aminoglycosides (streptomycin, gentamicin, tobramycin, amikacin, plazomicin) are bactericidal antibiotics binding the 30S ribosome, active against aerobic gram-negative bacilli, inactive against anaerobes, dosed once daily with narrow toxicity margins.

Oct 20, 2026

Aminoglycoside phosphotransferase

Aminoglycoside phosphotransferase (APH), or aminoglycoside kinase, a bacterial resistance enzyme that phosphorylates aminoglycoside antibiotics using ATP or GTP; seven subclasses including APH(3') and APH(2"), structurally related to eukaryotic protein kinases.

Oct 20, 2026

Aminoglycoside resistant Acinetobacter baumannii

Aminoglycoside resistant Acinetobacter baumannii refers to strains of the hospital pathogen A. baumannii that resist gentamicin, tobramycin, and amikacin, mainly through aminoglycoside-modifying enzymes, 16S rRNA methyltransferases, and efflux.

Aminoguanidine

Aminoguanidine, also known as pimagedine, is a hydrazine compound, formula CH6N4, first described in 1892 and developed as the first inhibitor of advanced glycation end products before trials failed.

Sep 29, 2026

Aminolevulinic acid photodynamic therapy

Aminolevulinic acid photodynamic therapy (ALA-PDT) is a treatment in which aminolevulinic acid is applied to abnormal skin, converted to protoporphyrin IX, and activated with light to destroy cells.

Aminonucleoside

An aminonucleoside is a nucleoside in which an amino group replaces a hydroxyl on the sugar or scaffold, covering antibiotic natural products such as puromycin and nucleocidin, produced by Streptomyces bacteria.

Aminooxyacetic acid

Aminooxyacetic acid (AOAA) is a hydroxylamine derivative of acetic acid and a broad inhibitor of pyridoxal phosphate-dependent enzymes, best known for blocking GABA-T and raising tissue GABA levels.

Aminopeptidase

Aminopeptidase (aminopeptidase Y, EC 3.4.11.15) is an exopeptidase that cleaves N-terminal peptide bonds to release free amino acids. Used in food protein hydrolysates, debittering, and cheese flavor; GRAS in the US (GRN 1048) and approved by FSANZ in 2025.

Aminopeptidase P

Aminopeptidase P, also called Xaa-Pro aminopeptidase (EC 3.4.11.9), is a metalloprotease that cleaves N-terminal amino acids linked to proline, found in bacteria, archaea, and mammals.