|
Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Equilibrium Density Gradient Centrifugation, ESR Spectroscopy
|
|
Equatorial plate The structure formed by the chromosomes in the centre (equatorial plane) of the spindle during mitosis.
Equilibrium 1. The point at which the concentration of two compounds are such that the interconversion of one compound to the other does not produce any change in free energy. 2. A state of dynamic systems in which there is no net change.
Equilibrium centrifugation A technique for separating proteins and nucleic acids from a mixture.
|
This involves subjecting the mixture to density gradient centrifugation to separate each component as a band at a point equal to its density
Equilibrium constant (keq) A constant that relates the specific concentration of all reactants and products at equilibrium at a given temperature and pressure. It is characteristic for each reaction.
Equilibrium density gradient centrifugation A technique used for the separation of macromolecules based on their density (mass per unit volume).
Equilibrium dialysis A technique used to measure antibody affinity.
|
Equilibrium potential The membrane potential at which there is no diffusion of an ion across the membrane. This is important in the generation of nerve impulse.
Equimolar Identical molar concentrations. See molarity; mole.
Equivalence zone The region of maximal precipitation in a precipitin reaction.
ER See endoplasmic reticulum.
ER lumen The space enclosed by the membranes of the endoplasmic reticulum (ER).
ER resident protein A protein that remains in the endoplasmic reticulum (ER) or its membranes and functions there.
|
|
ER retention signal A short amino acid sequence in a protein that prevents it from leaving the endoplasmic reticulum (ER). It is present in proteins that are resident in the ER.
ER signal sequence N-terminal signal sequence that directs proteins into the endoplasmic reticulum. After entry, it is cleaved by signal peptidase.
Erb-A One of the two oncogenes carried by the Avian erythroblastosis retrovirus which is identical to the gene encoding the thyroid hormone receptor protein. Erb is an acronym for Erythroblastosis.
Erb-B One of the two oncogenes carried by the Avian erythroblastosis retrovirus which is identical to the gene that codes for the epidermal growth factor receptor protein.
|
|
|
Erdos and Renyl law In a toss of ‘fair’ coin, the number of heads in arrow that can be expected is the logarithm of the number of tosses to the base 2. The base of the logarithm may be changed to the number of outcomes in order to generalize the law for more than two possible outcomes. This law is used to analyse the number of matches and mismatches between random sequences to score the statistical significance of a sequence alignment.
ERK (Extracellular Receptor Tyrosine Kinase). Transmembrane proteins that function as signal transducers for ligands that bind to the extracellular domains. Binding of the ligand activates a tyrosine kinase in the intracellular domain with phosphorylation of tyrosine residue(s) on intracellular proteins initiating a cascade of events
|
Erlenmeyer flask A conical flat-bottomed laboratory flask with a narrow neck that is widely used for culturing microorganism. This flask was designed by E.Erlenmeyer.
Error prone repair Part of the cellular response to extensive DNA damage termed the SOS response. It is derived from the fact that repair of pyrimidine dimmers is often inaccurate. See SOS repair response.
Erythema Redness of the skin resulting from congestion of the capillaries.
Erythroblast A bone marrow stem cell that is a precursor of erythrocytes.
Erythroblastosis foetalis A disorder associated with high concentration of bilirubin in amniotic fluid. The Haemolysis seen in this condition is generally caused by Rh incompatibility. An Rh-negative woman exposed to Rh-positive foetal blood during pregnancy responds by producing anti-D antibodies against antigens on foetal erythrocytes. When such a sensitized woman has a second Rh-positive foetus, the antibodies which are usually of the lgG class, cross the placenta causing destruction of foetal erythrocytes with consequent foetal anaemia, enhanced erythropoiesis, hepatic damage, and in severe cases, congestive cardiac failure, foetal oedema, ascites, and pleural and pericardial effusions. This condition referred to as hydrops foetalis, can result in death. If the foetus survives, the newborn is unable to conjugate the excess bilirubin resulting from Haemolysis because of liver damage. As a result bilirubin accumulates in circulation, passes through the blood brain barrier and gets deposited in the brain leading to destruction of brain cells. This conditionis termed kernicterus. Sensitisation of an Rh-negative mother on exposure to Rh-positive foetal erythrocytes after abortion and foetomaternal haemorrhage on delivery can be prevented by administration of anti Rho (D) immunoglobulin.
Erythrocyte (red blood cell, RBC) A blood cell that contains haemoglobin which transport oxygen and carbon dioxide.
Erythrocyte ghosts Red blood cells whose contents have been removed. These are used as carriers of drugs and other bioactive compounds to cells.
Erythromycin An inhibitor of prokaryotic protein biosynthesis that acts by binding to the 50S subunit and inhibits translocation.
Erythropoiesis Formation of erythrocytes.
Erythropoietin A growth factor produced in the kidney that acts on precursor cells in the bone marrow to stimulate the production of red blood cells.
ES cell See embryonic stem cells.
Escherichia coli (E.coli) A gram-negative bacterium commonly found in the intestine of vertebrates. It has been extensively used as a model system to study biochemical pathways, genetics and molecular biology and as a host for gene cloning experiments.
ESI cell See embryonic stem cells.
Escherichia coli (E.coli) A gram-negative bacterium commonly found in the intestine of vertebrates. It has been extensively used as a model system to study biochemical pathways, genetics and molecular biology and as a host for gene cloning experiments.
ESI Electrospray ionisation. A mass spectrometry technique that is suitable for the ionisation of large molecules such as proteins without significant degradation. See MALDI.
ESR spectroscopy See Electron spin resonance spectroscopy.
Essential amino acids Amino acids that cannot be synthesised by humans and must therefore be provided in the diet.
Essential element An element required by living organisms for normal growth, development and maintenance.
Essential fatty acids Polyunsaturated fatty acids that cannot be synthesized by humans and must therefore be provided in the diet.
Essential fructosuria A disorder of fructose metabolism caused due to lack of fructokinase. A diet low in fructose is beneficial.
Essential gene A gene whose dysfunction is lethal to the organism.
|
|
