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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Chimeric Clone - Cholectokinin CCK
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Chimeraplasty
An experimental targeted repair process in which a desirable sequences of DNA is combined with RNA to form a chimeraplast. The hybrid molecules bind selectively to the target DNA and activate a gene-correcting mechanism.
Chimeric antibody
An antibody encoded by genes from more than one species for example, antigen-binding regions from mouse genes and constant regions from human genes.
Chimeric clone
A cloning artifact created by a foreign gene that inserted into a vector in an incorrect orientation. This results in the expressions of a fusion protein that is a product of two genes.
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Chimeric DNA
A recombinant DNA molecule containing unrelated genes from different organisms.
Chimeric gene
A semi-synthetic gene, containing the coding sequence from one organism, fused to a promoter and other sequences derived from a different gene. Most genes used in transformation are chimeric.
Chimeric/humanized antibodies
Engineering an antibody in such a way that it looks like a human antibody to the human system. This involves replacing the constant regions of the mouse antibody with those of a human antibody to produce a protein that binds to an antigen like an original monoclonal antibody.
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Chimeric Protein
See fusion protein
Chimeric selectable marker gene
A gene constructed from parts of two or more different genes that allows the host organism to survive under conditions where it would normally die.
Chip, DNA
See DNA chip.
Chiral center
An atom with substituents arranged in such a way that the molecule is not superimposable on its mirror image.
Chiral Compound
A Compound capable of existing in two forms that are nonsuperimposable images of each other.
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Chitinase
An enzyme that breaks down chitin.
Chloramphenicol
An inhibitor of prokaryotic protein biosynthesis that inhibits peptidyltransferase present on 50S subunit and blocks peptide bond formation.
Chloramphenicol acetyltransferase (CAT) assay
An assay that is used follow the activity of a eukaryotic promoter. The protocol involves: i. introduction of CAT-containing plasmid into eukaryotic cells ii. growth of the cells for 72 h followed by preparation of the cell extract, iii. addition of 14C-chloramphenicol to the supernatant and incubation for 60 minutes, iv. acetylation of chloramphenicol by CAT.
Separation of the acetylated and non-acetylated forms by thin layer chromatography, and v. measurement of the ability of the cell extract to acetylate chloramphenicol. The enzyme activity corresponds to the activity of the eukaryotic promoter.
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Chloride Shift
Diffusion of Cl- from the plasma into the RBCs in exchange for HCO3 to maintain electrochemical neutrality during CO2 transport.
Chlorophyll
(Gr, chloros, green + phyllon, leaf). A green photosynthetic pigment that functions as a receptor for light energy during photosynthesis. It is a magnesium porphyrin complex and is one of the two pigments responsible for the green colour of most plants.
Chloroplast
(Gr. chloros, green + plastos, formed). A chlorophyll-containing specialised cytoplasmic organelle present in eukaryotic cells. It is lens-shaped and bounded by a double membrane.
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Chloroplasts contain membranous structures called thylakoids that are piled up into stacks, surrounded by a gel-like matrix termed stroma.
They harness light energy and are the sites for important reactions of starch or sugar synthesis. Chloroplasts have their own DNA and exhibit cytoplasmic inheritance that is independent of nuclear genes.
Chiral Synthesis
The chemical synthesis of chiral compounds in only one enantiomers by resolution or synthetic methods such as asymmetric catalysis, biotransformation or fermentation.
Chirality
The nonidentity of a compound with its mirror image. The ability of a compound to bind to four different groups. See enantiomers.
Chitin
A nitrogenous polysaccharide that functions as skeletal material in many invertebrates and fungi. It is composed of N-acetyl-D-glucosamine units joined by β(1→ 4) glucosidic linkages.
Chloroplastid
See chloroplast
Chlorpropamide
See sulphonylureas
CHO Cells
A cell line derived from the ovary of the Chinese hamster, Cricetulus griseus that functions as a model system for the study of genetic alteration in cultured mammalian cells. The species is useful or cytogenetic studies because of its small chromosome number.
Cholangitis
Inflammation of a bile duct
Cholecalciferol
Vitamin D3 formed from 7-dehydrocholesterol by the action of sunlight on skin. It undergoes hydroxylation in the liver, catalysed by the enzyme 25-hydrosylase to from 25-hydroxy D3 (calcidiol). In the kidney, Calcidiol is hydroxylated to from the biologically from 1, 25-dihydrdroxycholecalciferol (calcitriol). The reaction is catalysed by 1 α-hydroxylase present in the proximal renal tubule cells.
Cholecalciferol
Cholecystectomy
Removal of the gallbladder.
Cholecystokinin (CCK)
A gastrointestinal hormone that causes contraction of gallbladder with release of bile into the small intestine and stimulation of pancreatic enzyme secretion. It is released by the presence of lipids and polypeptides in the gut action of CCK is mediated by mobilization of Ca2+ stores.
Cholestasis
Arrest or suppression of bile flow.
Cholesterol
A lipid molecule with a four-ring steroid structure (cyclopentanoperhydrophenanthrene). It is present in high concentrations in nervous tissue, plasma membrane and in lipoproteins. Approximately two thirds of plasma cholesterol is esterified with fatty acids to from cholesterol esters. Cholesterol is a precursor of many biologically important steroid compounds such as bile acids, steroid hormones and vitamin D.
Cholesterol
Cholesterol ester hydrolase
An enzyme that hydrolyses cholesteryl esters to from free cholesterol and fatty acids.
Cholestyramine
A bile acid-binding resin useful in high risk patients with atherosclerosis. It acts by increasing sterol excretion and receptor mediates catabolism of LDL thereby decreasing LDL cholesterol.
cholinergic
Relating to nerve fibres that release acetylcholine.
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