| C type lectin | <cell biology> One of two classes of lectin produced by animal cells, the other being the S type. The C type lectins require disulphide linked cysteines and Ca ions in order to bind to a specific carbohydrate (c.f. S type lectins). The carbohydrate recognition domain of C type lectins consists of about 130 amino acids which contains 18 invariant residues in a highly conserved pattern. These invariant residues include cysteines which probably form disulphide bonds. So far, all identified C type lectins are extracellular proteins and include both Integral membrane proteins, such as the asialoglycoprotein receptor and soluble proteins. (06 Aug 1998) |
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| C type virus | <molecular biology, virology> Originally C type particles identified in mouse tumour tissue and later shown to be oncogenic RNA viruses Oncovirinae) that bud from the plasma membrane of the host cell starting as a characteristic electron dense crescent. Include feline leukaemia virus, murine leukaemia and sarcoma viruses. (18 Nov 1997) |
| C value | <molecular biology> A measure of the amount of DNA in the haploid genome of an organism, which can be by mass or by molecular weight. (13 Nov 1997) |
| C value paradox | <molecular biology> Comparison of the amount of DNA present in the haploid genome of different organisms (the C value) reveals two problems: the value can differ widely between two closely related species and there seems to be far more DNA in higher organisms than could possibly be required to code for the modest increase in complexity. (21 May 1997) |
| C wave | 1. A monophasic positive deflection in the electroretinogram arising in the pigment epithelium of the retina. 2. Wave in the venous and atrial pulses occurring during isovolumic ventricular contraction in which the closed atrioventricular valves (mitral and tricuspid) are abruptly displaced into the atria with a creation of a pressure transient. (05 Mar 2000) |
| C-10-deacetylase | <enzyme> An intracellular enzyme that specifically removes the 10-acetate from baccatin III and paclitaxel; produced by nocardioides luteus; mw 40 kD Registry number: EC 3.1.1.- Synonym: c10-deacetylase (26 Jun 1999) |
| C-13-deacylase | <enzyme> An extracellular enzyme that specifically removes the c-13 side chain from paclitaxel and other taxanes to produce baccatin-iii; produced by nocardioides albus; mw 47 kD Registry number: EC 3.1.1.- Synonym: c13-deacylase (26 Jun 1999) |
| C-banding stain | <technique> A selective chromosome banding stain used in human cytogenetics, employing Giemsa stain after most of the DNA is denatured or extracted by treatment with alkali, acid, salt, or heat; only heterochromatic regions close to the centromeres and rich in satellite DNA stain, with the exception of the Y chromosome whose long arm usually stains throughout. Synonym: centromere banding stain. (05 Mar 2000) |
| c-Jun amino-terminal kinase | <enzyme> A stress-activated protein kinase; 46-kD kinase that phosphorylates ser(63) and ser(73) of c-jun; similar to yeast hog1 kinase; amino acid sequence given in second source; genbank l23118 Registry number: EC 2.7.10.- Synonym: jn kinase, jnk1 protein kinase, jnk-46, jnk1 protein, jun-nh2-terminal kinase, stress-activated protein kinase 1, sap kinase-1, sapk1, p46 sap kinase, c-jun kinase-1 (26 Jun 1999) |
| c-oncogene | <molecular biology> A normal gene which has a tumour-producing insert that may have originated from a virus in it, turning it into a proto-oncogene. When these genes are sufficiently mutated, amplified, or over-expressed (transcribed too many times), they can begin to produce cancers. (05 Jan 1998) |
| c-peptide | <protein> C-peptide is a byproduct of normal insulin production by the beta cells in the pancreas. Normal values are 0.5 to 3.0 ng/ml. Normal levels indicate that the body is still producing its own insulin. Low levels indicate that the pancreas is producing little or no insulin. Elevations can be seen in cases of insulinomas and islet of Langerhans tumours. (27 Sep 1997) |
| C-reactive protein | <protein> This blood test is used as an indicator of acute inflammation. C-reactive protein is a protein of the pentraxin family, produced by the liver during periods of inflammation and detectable in serum in various disease conditions particularly during the acute phase of immune response. Normally C-reactive protein should be negative in the bloodstream. C-reactive protein is synthesised by hepatocytes and its production may be triggered by prostaglandin E1 or parogen. It consists of five polypeptide sub units forming a molecule of total molecular weight 105 kD. It binds to polysaccharides present in a wide range of bacterial, fungal and other cell walls or cell surfaces and to lecithin and to phosphoryl or choline containing molecules. It is related in structure to Serum Amyloid. And C polysaccharide. Conditions which can cause a positive C-reactive protein include: rheumatoid arthritis, lupus, pneumococcal pneumonia, rheumatic fever, cancer, tuberculosis and myocardial infarction. A positive C-reactive protein may also be seen in the later half of pregnancy and in some who are taking birth control pills. See: acute phase proteins (06 Oct 1997) |
| C-section | A surgical procedure that involves the delivery of the foetus through an abdominal incision. C-sections account for about 1/5 of all births in the us. Indications include: failure to progress, foetal distress, cephalopelvic disproportion (baby's too big for birth canal), placenta previa, placental abruption, placental insufficiency, breech baby, active genital herpes, multiple gestation, preeclampsia and excessive scarring from previous surgeries. The average hospital stay is about 4 days. The maternal death rate with C-section is three times higher than with natural delivery. (27 Sep 1997) |
| C-terminal leucine protein methyltransferase | <enzyme> Reversibly modifies protein phosphatase 2a by methyl esterification at its c-terminal leucine residues Registry number: EC 2.1.1.- Synonym: tlp methyltransferase (26 Jun 1999) |
| C-terminus | The end of a peptide or protein having a free carboxyl (-COOH) group. (05 Mar 2000) |