| proton acceptor | <chemistry> A base, an anionic substance that acceptsa proton during an acid-basereaction. (09 Oct 1997) |
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| membrane-bound proton-translocating PPi synthase | <enzyme> From rhodospirillum rubrum; functions as an alternative coupling factor; n,n'-dicyclohexylcarbodiimide-sensitive; catalyses the phosphorylation of pi to ppi, the hydrolysis of ppi and the concomitant translocation of proton across the plasma membrane Registry number: EC 3.6.1.- Synonym: h(+)-ppi synthase (26 Jun 1999) |
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| proton | <physics> An elementary atomic particle with a positive charge and a mass of about 1 amu. (09 Oct 1997) |
| proton ATPase | <enzyme> An ion pump that actively transports hydrogen ions across lipid bilayers in exchange for ATP. Major groups are the F-type ATPases, that run in reverse to synthesise ATP in bacterial, mitochondrial and chloroplast membranes (ATP synthase) and the V-type ATPases found in intracellular vesicles with an acidic lumen and on certain epithelial cells (e.g. Kidney intercalated cells). Gastric H/K ATPase is a proton ATPase. (18 Nov 1997) |
| proton donor | <chemistry> An acid, a susbstance that donates protons in an acid-base reduction reaction. (10 Jan 1998) |
| proton-motive force | Energy that is generated by the transfer of protons or electrons across an energy-transducing membrane and that can be used for chemical, osmotic, or mechanical work. Proton-motive force can be generated by a variety of phenomena including the operation of an electron transport chain, illumination of a purple membrane, and the hydrolysis of ATP by a proton atpase. (12 Dec 1998) |
| proton pump | Integral membrane proteins that transport protons across a membrane against a concentration gradient. This transport is driven by hydrolysis of ATP by hydrogen-transporting ATP synthase. (12 Dec 1998) |
| proton pump inhibitor | <pharmacology> A group of anti-ulcer medications which work by binding to H+/K+ ATPase, an enzyme which is found on the secretory surface of parietal cells. It thereby inhibits the final transport of hydrogen ions (via exchange with potasium) into the gastric lumen. Examples of proton pump inhibitors include omeprazole and lansoprazole. (27 Sep 1997) |
| acceptor | A compound that will take up a chemical group (e.g., an amine group, a methyl group, a carbamoyl group) from another compound (the donor); under the action of alanine transaminase, l-glutamic acid is an amine donor while pyruvic acid is an amine acceptor. Origin: L. Ac-cipio, pp. -ceptus, to accept (05 Mar 2000) |
| acceptor control | <biochemistry> The regulation of the respiration rate, governed by ADP's ability to be a phosphate group acceptor. (06 May 1997) |
| acceptor RNA | rNA |
| acceptor site | The ribosomal binding site for the aminoacyl-tRNA during protein synthesis. (05 Mar 2000) |
| acceptor splicing site | Boundary between the right end of an intron and the left end of the adjacent exon. Synonym: acceptor splicing site. (05 Mar 2000) |
| alcohol dehydrogenase (acceptor) | An oxidoreductase that reversibly converts primary alcohols to aldehydes with an H acceptor other than NADP+. (05 Mar 2000) |
| phenylglyoxylate - acceptor oxidoreductase | <enzyme> Requires coenzyme a; converts phenylglyoxylate to benzoyl-CoA with release of co2 Registry number: EC 1.2.99.- Synonym: phenylglyoxylate oxidoreductase (acylating) (26 Jun 1999) |
| hydrogen acceptor | A molecule that, in conjunction with a tissue enzyme system, carries hydrogen from one metabolite (oxidant) to another (reductant) or to molecular oxygen to form H2O. Synonym: hydrogen acceptor. (05 Mar 2000) |