| lecithinase A | <enzyme> An enzyme that catalyses the hydrolysis of a lecithin to a lysolecithin by removing the 2-acyl group; also acts on other phospholipids by removing a fatty acid from the 2-position; this enzyme has an important role in prostaglandin and leukotriene biosynthesis. Synonym: lecithinase A, phosphatidase, phosphatidolipase. (05 Mar 2000) |
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| lecithinase B | <enzyme> An enzyme that catalyses the hydrolysis of a single fatty acid ester bond in lysoglycerophosphatidates with the formation of glyceryl phosphatidates and a fatty acid. Chemical name: 2-Lysophosphatidylcholine acylhydrolase Registry number: EC 3.1.1.5 (12 Dec 1998) |
| lecithinase C | <enzyme> An enzyme found in the alpha-toxin of clostridium welchii and other strains of clostridia and bacilli. It hydrolyzes glycerophosphatidates with the formation of 1,2-diacylglycerol and a phosphorylated nitrogenous base such as choline. Chemical name: Phosphatidylcholine cholinephosphohydrolase Registry number: EC 3.1.4.3 (12 Dec 1998) |
| lecithinase D | <enzyme> An enzyme found mostly in plant tissue. It hydrolyzes glycerophosphatidates with the formation of a phosphatidic acid and a nitrogenous base such as choline. This enzyme also catalyses transphosphatidylation reactions. Chemical name: Phosphatidylcholine phosphatidohydrolase Registry number: EC 3.1.4.4 (12 Dec 1998) |
| lecithoblast | One of the cells proliferating to form the yolk-sac endoderm. Origin: G. Lekithos, egg yolk, + blastos, germ (05 Mar 2000) |
| lecithoprotein | A conjugated protein, with lecithin as the prosthetic group. (05 Mar 2000) |
| lecithovitellase | <chemical> Chemical name: lecithovitellase (26 Jun 1999) |
| Leclef phenomenon | Enhanced phagocytosis by leukocytes of microorganisms in the presence of immune serum. (05 Mar 2000) |
| LeCompte manoeuvre | <procedure, surgery> A repair of double outlet right ventricle with pulmonary stenosis and other abnormalities of ventricular arterial connection and ventricular septal defect. The left ventricle is connected to the aorta and the right ventricle to the pulmonary artery using a technique that does not require an extracardiac conduit. Synonym: LeCompte operation. (05 Mar 2000) |
| LeCompte operation | <procedure, surgery> A repair of double outlet right ventricle with pulmonary stenosis and other abnormalities of ventricular arterial connection and ventricular septal defect. The left ventricle is connected to the aorta and the right ventricle to the pulmonary artery using a technique that does not require an extracardiac conduit. Synonym: LeCompte operation. (05 Mar 2000) |
| lectin | <plant biology> Proteins obtained particularly from the seeds of leguminous plants, but also from many other plant and animal sources, that have binding sites for specific mono or oligosaccharides in cell walls or membranes. They thereby change the physiology of the membrane to cause agglutination, mitosis, or other biochemical changes in the cell. Named originally for the ability of some to selectively agglutinate human red blood cells of particular blood groups. Lectins such as concanavalin A and wheat germ agglutinin are widely used as analytical and preparative agents in the study of glycoproteins. (21 Jun 2000) |
| lection | 1. A lesson or selection, especially. Of Scripture, read in divine service. 2. A reading; a variation in the text. "We ourselves are offended by the obtrusion of the new lections into the text." (De Quincey) Origin: L. Lectio, fr. Legere, lectum, to read. See lesson, Legend. Source: Websters Dictionary (01 Mar 1998) |
| lectionary | Origin: LL. Lectionarium, lectionarius: cf. F. Lectionnaire. A book, or a list, of lections, for reading in divine service. Source: Websters Dictionary (01 Mar 1998) |
| lector | A reader of lections; formerly, a person designated to read lessons to the illiterate. Origin: L. See Lection. Source: Websters Dictionary (01 Mar 1998) |
| lectotype | <zoology> One of several syntypes, designated by any author after the original publication of a species name as the type specimen for the taxonomic name. Designated only where there was no original holotype. (09 Jan 1998) |