| LCC | lactose coliform count; left circumflex coronary (artery); left common carotid; left coronary cusp; ... |
|---|---|
| LFD | lactose-free diet; large for date [fetus]; late fetal death; lateral facial dysplasia; least fatal d... |
| LI | labeling index; lactose intolerance; lacunar infarct; lamellar ichthyosis; Langerhans islet; large i... |
| LM | lactic acid mineral [medium]; lactose malabsorption; laryngeal mask; laryngeal muscle; lateral malle... |
| LSU | lactose-saccharose-urea [agar]; life support unit |
| lactose factors | Plasmids which determine the ability of a bacterium to ferment lactose. (12 Dec 1998) |
|---|---|
| lactose intolerance | A disorder characterised by abdominal cramps and diarrhoea after the consumption of food containing lactose (for example milk, ice cream), believed to occur due to a deficiency of intestinal lactase (enzyme that breaks down lactose), may appear first in young adults who have previously tolerated milk well as infants. (27 Sep 1997) |
| lactose operon | Group of adjacent and coordinately controlled genes concerned with the metabolism of lactose in E. Coli. The lac operon was the first example of a group of genes under the control of an operator region to which a lactose repressor binds. When the bacteria are transferred to lactose containing medium, allolactose (which forms by transglycosylation when lactose is present in the cell) binds to the repressor, inhibits the binding of the repressor to the operator and allows transcription of mRNA for enzymes involved in galactose metabolism and transport across the membrane (_ galactosidase, galactoside permease and thiogalactoside transacetylase). (18 Nov 1997) |
| lactose permease | <chemical> Chemical name: permease, lactose Synonym: lactose carrier protein, lactose permease m protein, lac permease, lactose transport protein, lactose transport system, lac carrier protein, lacs protein, lactose transport system, streptococcus thermophilus, lacy protein (26 Jun 1999) |
| lactose repressor | Protein (tetramer of 37 kD subunits) that normally binds with very high affinity to the operator region of the lactose operon and inhibits transcription of the downstream genes by blocking access of the polymerase to the promoter region. When the lactose repressor binds allolactose, its binding to the operator is reduced and the gene set is derepressed. (18 Nov 1997) |
| lactose synthase | <enzyme> An enzyme of the transferase class that catalyses the transfer of galactose from udpgalactose to glucose, forming lactose. The enzyme is a complex of the enzyme n-acetyllactosamine synthase and alpha-lactalbumin; the latter protein is present in lactating mammary gland cells where it alters the usual specificity of the former to make lactose synthesis the preferred reaction. Chemical name: UDPgalactose:D-glucose 4-beta-D-galactosyltransferase Registry number: EC 2.4.1.22 (12 Dec 1998) |