| hydrogen-transporting ATP synthase | <enzyme> A group of enzymes which are involved in the reversible synthesis of ATP and that transport protons from the cytoplasmic to the matrix side of the mitochondrial membrane. The flow of protons through the f(0) channel results in ATP synthesis by f1. Chemical name: ATP phosphohydrolase (H+-transporting) Registry number: EC 3.6.1.34 (12 Dec 1998) |
|---|---|
| sodium-hydrogen antiporter | A plasma membrane exchange glycoprotein transporter that functions in intracellular pH regulation, cell volume regulation, and cellular response to many different hormones and mitogens. (12 Dec 1998) |
| sodium hydrogen carbonate | <chemical> Carbonic acid monosodium salt (CHNaO3). A white, crystalline powder that is used as an electrolyte replenisher and systemic alkaliser. It is applied topically in solution to wash the nose, mouth, or vagina, and as a cleansing enema. Pharmacologic action: Acid neutralization. Uses: Preexisting metabolic acidosis, hyperkalemia, tricyclic or phenobarbital overdose. Dose in mEq: 0.3 * (base deficit) * (wt in kg). Potential complications: Metabolic alkalosis, hypercarbia, hyperosmolar state. Note: Since HCO3- does not cross cell membranes and CO2 does, the administration of bicarbonate may actually make tissues more acidotic. Chemical name: Carbonic acid monosodium salt. (12 Mar 2000) |
| sodium hydrogen sulfite | NaHSO3;acid sodium sulfite, used in gastric and intestinal fermentation, externally in the treatment of parasitic diseases, and as an antioxidant in certain injections (s. Metabisulfite). Synonym: sodium hydrogen sulfite, sodium pyrosulfite. (05 Mar 2000) |
| sulfureted hydrogen | <chemical> Hydrogen sulfide (h2s). A flammable, poisonous gas with a characteristic odour of rotten eggs. It is used in the manufacture of chemicals, in metallurgy, and as an analytical reagent. Chemical name: Hydrogen sulfide (H2S) (12 Dec 1998) |
| interspecies hydrogen transfer | <biology, ecology> The process in which organic matter is degraded anaerobically by the interaction of several groups of microorganisms in which hydrogen production and hydrogen consumption are closely coupled among species. (09 Oct 1997) |
| 3-chloro-D-alanine hydrogen chloride-lyase | <enzyme> Pseudomonas putida enzyme; forms cysteine from 3-chloro-d-alanine and hydrogen sulfide Registry number: EC 4.5.- Synonym: cahc-lyase, 3-chloro-d-alanine chloride-lyase (deaminating) (26 Jun 1999) |
| formate hydrogen lyase | <enzyme> Consists of EC 1.2.1.2, formate dehydrogenase, plus EC 1.12.1.2, hydrogen dehydrogenase Registry number: EC 1.- Synonym: formate dehydrogenase h, fdhh gene product, fdhf gene product, hyc gene product (26 Jun 1999) |
| active | Characterised by action, not passive, not expectant. (18 Nov 1997) |
| active acetate | <enzyme> Condensation product of coenzyme A and acetic acid, symbolised as CoAS~COCH3; intermediate in transfer of two-carbon fragment, notably in its entrance into the tricarboxylic acid cycle and in fatty acid synthesis. This coenzyme plays a huge role in intermediary metabolism, in which cells synthesise, break down or use nutrient molecules for energy production, growth, etc. Acetyl-coenzyme A synthase is found in bacteria and plants and catalyses the reaction in which acetate enters metabolic pathways and forms acetyl-coenzyme A. Synonym: acetyl-coenzyme A, active acetate. (05 Mar 2000) |
| active aldehyde | Any aldehyde derivative of thiamin pyrophosphate. (05 Mar 2000) |
| active anaphylaxis | Reaction following inoculation of antigen in a subject previously sensitised to the specific antigen, in contrast to passive anaphylaxis. (05 Mar 2000) |
| active biomass | <cell biology> The amount of a given culture that is actively growing. (06 May 1997) |
| active carbon dioxide | Activated carbon dioxide, a complex of N-carboxybiotin (biotin + CO2) and an enzyme; the form in which carbon dioxide is added to other molecules in carboxylations; e.g., to methylcrotonyl-CoA to form beta-methylglutaconyl in the catabolism of leucine, and to acetyl-CoA to form malonyl-CoA. See: acetyl-CoA carboxylase. (05 Mar 2000) |
| active caries | Microbial-induced lesions of teeth that are increasing in size. (05 Mar 2000) |