| o-dihydricphenol meta-O-methyltransferase | <enzyme> Involved in flavone glycoside biosynthesis Registry number: EC 2.1.1.- Synonym: dhcp-mtf (26 Jun 1999) |
|---|---|
| o-diphenolase | <enzyme> An enzyme of the oxidoreductase class that catalyses the reaction between catechol and oxygen to yield benzoquinone and water. It is a complex of copper-containing proteins that acts also on a variety of substituted catechols. Chemical name: 1,2-Benzenediol:oxygen oxidoreductase Registry number: EC 1.10.3.1 (12 Dec 1998) |
| O-phosphocholine | (CH3)3N+-CH2 CH2-OPO3 H-; choline O-phosphate;important in choline metabolism, e.g., as in cytidinediphosphocholine and in the biosynthesis of lecithins. Synonym: O-phosphocholine, phosphorylcholine. Phosphocholine cytidylyltransferase, an enzyme that catalyses the reaction of phosphocholine with CTP to form pyrophosphate and CDP-choline; the rate-limiting step of lecithin biosynthesis; the cytosolic form of the enzyme is inactive (a phosphorylated form of the enzyme). Phosphocholine diacylglycerol transferase, an enzyme in lecithin biosynthesis that catalyses the reaction of 1,2-diacylglycerol with CDP-choline to form CMP and phosphatidylcholine. (05 Mar 2000) |
| O-phosphono- | <prefix> Prefix indicating a phosphonic acid radical (-PO3H2) attached through an oxygen atom, hence a phosphoric ester. See: phospho-. (05 Mar 2000) |
| O-phosphoserine | 2-O3 P- OCH2CH(NH3)+COO-;the phosphoric ester of serine; found as a constituent in many proteins (e.g., phosphorylase a and phosvitin). (05 Mar 2000) |
| o-phthalaldehyde | <chemical> 1,2-benzenedicarboxaldehyde. A reagent that forms fluorescent conjugation products with primary amines. It is used for the detection of many biogenic amines, peptides, and proteins in nanogram quantities in body fluids. Pharmacological action: disinfectants, indicators and reagents. Chemical name: 1,2-Benzenedicarboxaldehyde (12 Dec 1998) |
| o-point | <physics> Place where the poloidal magnetic field vanishes in such a way that the nearby flux surfaces are elliptical, for example on the magnetic axis or at the centre of a magnetic island. (See also X-Point.) (09 Oct 1997) |
| O-R system | <abbreviation> Oxidation-reduction system. (05 Mar 2000) |
| O-sialoglycoprotein endopeptidase | <enzyme> Specific for o-sialoglycoproteins such as glycophorin a; amino acid sequence given in first source Registry number: EC 3.4.24.57 Synonym: pht a1 glycoprotease, o-glycosylated glycoprotein protease, sialoglycoprotease, glycophorin a protease, glycophorin a glycoprotease, glycoprotease, pasteurella haemolytica a1 (26 Jun 1999) |
| o-succinylbenzoic acid synthase | <enzyme> E coli enzyme; with shchc synthase catalyses formation of o-succinylbenzoic acid from isochorismic acid and alpha-ketoglutarate in presence of thiamine pyropyrophosphate; succinic saemialdehyde anion is formed by decarboxylation of alpha-ketoglutarate by thiamine pyrophosphate; anion then attacks isochorismic acid, initiating aromatization with elimination of pyruvate and h2o Registry number: EC 4.1.99.- Synonym: ortho-succinylbenzoic acid synthase, osb synthase, 2-succinylbenzoic acid synthase (26 Jun 1999) |
| O-succinylhomoserine (thiol)-lyase | <enzyme> An enzyme catalyzing the reaction between cystathionine and succinate to form l-cysteine and O-succinyl-l-homoserine. Synonym: cystathionine gamma-synthase. (05 Mar 2000) |
| oafish | Like an oaf; simple. Oaf"ishness. Source: Websters Dictionary (01 Mar 1998) |
| oak | 1. <botany> Any tree or shrub of the genus Quercus. The oaks have alternate leaves, often variously lobed, and staminate flowers in catkins. The fruit is a smooth nut, called an acorn, which is more or less inclosed in a scaly involucre called the cup or cupule. There are now recognised about three hundred species, of which nearly fifty occur in the United States, the rest in Europe, Asia, and the other parts of North America, a very few barely reaching the northern parts of South America and Africa. Many of the oaks form forest trees of grand proportions and live many centuries. The wood is usually hard and tough, and provided with conspicuous medullary rays, forming the silver grain. 2. The strong wood or timber of the oak. Among the true oaks in America are: Barren oak, or Black-jack, Q. Nigra. Basket oak, Q. Michauxii. Black oak, Q. Tinctoria: called also yellow or quercitron oak. Bur oak (see under Bur), Q. Macrocarpa; called also over-cup or mossy-cup oak. Chestnut oak, Q. Prinus and Q. Densiflora. Chinquapin oak (see under Chinquapin), Q. Prinoides. Coast live oak, Q. Agrifolia, of California; also called enceno. Live oak (see under Live), Q. Virens, the best of all for shipbuilding; also, Q. Chrysolepis, of California. Pin oak. Same as Swamp oak. Post oak, Q. Obtusifolia. Red oak, Q. Rubra. Scarlet oak, Q. Coccinea. Scrub oak, Q. Ilicifolia, Q. Undulata, etc. Shingle oak, Q. Imbricaria. Spanish oak, Q. Falcata. Swamp Spanish oak, or Pin oak, Q. Palustris. Swamp white oak, Q. Bicolour. Water oak, Q. Aguatica. Water white oak, Q. Lyrata. Willow oak, Q. Phellos. Among the true oaks in Europe are: Bitter oak, or Turkey oak, Q. Cerris (see Cerris). Cork oak, Q. Suber. English white oak, Q. Robur. Evergreen oak, Holly oak, or Holm oak, Q. Ilex. Kermes oak, Q. Coccifera. Nutgall oak, Q. Infectoria. Among plants called oak, but not of the genus Quercus, are: African oak, a valuable timber tree (Oldfieldia Africana). Australian, or She, oak, any tree of the genus Casuarina (see Casuarina). Indian oak, the teak tree (see Teak). Jerusalem oak. See Jerusalem. New Zealand oak, a sapindaceous tree (Alectryon excelsum). Poison oak, the poison ivy. See Poison. Silky, or Silk-bark, oak, an Australian tree (Grevillea robusta). Green oak, oak wood coloured green by the growth of the mycelium of certain fungi. Oak apple, a large, smooth, round gall produced on the leaves of the American red oak by a gallfly (Cynips confluens). It is green and pulpy when young. <zoology> Oak beauty, a British geometrid moth (Biston prodromaria) whose larva feeds on the oak. Oak gall, a gall found on the oak. See Gall. <botany> Oak leather See Pruner, the insect. Oak spangle, a kind of gall produced on the oak by the insect Diplolepis lenticularis. Oak wart, a wartlike gall on the twigs of an oak. The Oaks, one of the three great annual English horse races (the Derby and St. Leger being the others). It was instituted in 1779 by the Earl of Derby, and so called from his estate. To sport one's oak, to be "not at home to visitors," signified by closing the outer (oaken) door of one's rooms. Origin: OE. Oke, ok, ak, AS. Ac; akin to D. Eik, G. Eiche, OHG. Eih, Icel. Eik, Sw. Ek, Dan. Eeg. Source: Websters Dictionary (01 Mar 1998) |
| oak apple | An excrescence on the oak, Quercus infectoria (family Fagaceae) and other species of Quercus, caused by the deposit of the ova of a fly, Cynips gallae tinctorae; an astringent and styptic, by virtue of the tannin it contains. Synonym: gall, galla, oak apple. (05 Mar 2000) |
| oaken | Made or consisting of oaks or of the wood of oaks. "In oaken bower." "Oaken timber, wherewith to build ships." (Bacon) Origin: AS. Acen. Source: Websters Dictionary (01 Mar 1998) |