| meso compound | <chemistry> A compound that has two or more chiral centres but does not rotate plane-polarized light because it has an internal plane of symmetry. These compounds are identical to their mirror images. (09 Jan 1998) |
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| meso compounds | Compounds containing more than one asymmetric carbon atom, with configurations about them so balanced that the molecule as a whole possesses a plane of symmetry, although the individual carbon atoms do not; such compounds are not optically active; e.g., ribitol, mucic acid, meso-inositol, meso-cystine. (05 Mar 2000) |
| meso- | Mes- 1. Middle, mean, intermediacy. 2. A mesentery, mesentery-like structure. 3. A prefix denoting a compound, containing more than one chiral centre, having an internal plane of symmetry; such compounds do not exhibit optical activity (e.g., meso-cystine). Origin: G. Mesos (05 Mar 2000) |
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| meso-cystine | An isomer of cystine in which the configuration about one of the alpha-carbons is d, about the other, l, so that the molecule as a whole possesses a plane of symmetry and is optically inactive. Note that meso-cystine is not dl-cystine. Dl-cystine is a racaemic mixture of dd-cystine and ll-cystine. (05 Mar 2000) |
| meso-inositol | 1. Generic term for any isomer of meso-inositol in which the hydroxyl groups are so arranged that the molecule as a whole possesses a plane of symmetry and is optically inactive. 2. Former name for myo-inositol. (05 Mar 2000) |
| meso-ontomorph | A broad, stocky individual. Origin: meso-+ G. On, being, + morphe, form (05 Mar 2000) |
| meso-tartrate dehydrogenase | <enzyme> Forms dihydroxyfumarate; distinguished from EC 1.1.1.93 which forms oxaloglycollate Registry number: EC 1.3.1.7 (26 Jun 1999) |
| acetone compound | <biochemistry> Any of the three compounds created by acetyl coenzyme A (acetoacetate, hydroxybutyrate, and acetone) which are water-soluble cellular fuels normally exported by the liver. They can build up in the blood and body tissues because of starvation, untreated diabetes mellitus, or other disorders that interfere with carbohydrate metabolism. The body rids itself of ketones mainly through urine, but it rids itself of acetone through the lungs, which gives the breath a characteristic fruity odour. If ketones build up in the body long enough, they cause serious illness and coma (see ketoacidosis.) (09 Oct 1997) |
| acyclic compound | An organic compound in which the chain does not form a ring. Synonym: aliphatic compound, open chain compound. (05 Mar 2000) |
| addition compound | Strictly, a complex of two or more complete molecules in which each preserves its fundamental structure and no covalent bonds are made or broken (e.g., hydrates of salts, adducts), loosely, association of acids with basic organic compound's (e.g., amines with HCl), more loosely, addition of two molecules without loss of any atom, but forming new covalent bonds (e.g., CH2==CH2 + Br2 → BrCH2-CH2Br). (05 Mar 2000) |
| aliphatic compound | An organic compound in which the chain does not form a ring. Synonym: aliphatic compound, open chain compound. (05 Mar 2000) |
| APC compound | An analgesic tablet drug combination containing aspirin, phenacetin and caffeine. Very widely used in the 1940's through 1960's; original constituents of popular over-the-counter pain remedies. Use currently much diminished due to concerns about potential renal injury due to the phenacetin. (05 Mar 2000) |
| aromatic compound | Any compound in which the constituent atoms, or any part of them, form a ring. Used mainly in organic chemistry where: 1) numerous compound's contain rings of carbon atoms (carbocyclic compound's) or carbon atoms plus one or more atoms of other types (heterocyclic compound's), usually nitrogen, oxygen, or sulfur; 2) where the atoms in the ring are all of the same element (homocyclic or isocyclic compound); 3) where the ring is saturated or contains nonconjugated double bonds (alicyclic compound), the compound is similar in properties to the corresponding acyclic compound (e.g., cyclohexane resembles hexane); 4) where the ring contains conjugated double bonds in a closed loop in which there are 4n + 2 (where n is an integer) delocalised π electrons (Huckel's rule) (aromatic compound; e.g., benzene, pyridine), it is more stable than the corresponding saturated ring and exhibits unusual chemical properties characteristic of itself and not of other types of rings or of acyclic compound's. These aromatic compounds have the ability to sustain an induced ring current. Synonym: closed chain compound, ring compound. (05 Mar 2000) |
| binary compound | <chemistry> This refers to any compound that is composed of only two elements. (09 Oct 1997) |
| calcium compound | Inorganic compounds that contain calcium as an integral part of the molecule. (12 Dec 1998) |
| carbamino compound | Any carbamic acid derivative formed by the combination of carbon dioxide with a free amino group to form an N-carboxy group, -NH-COOH, as in haemoglobin forming carbaminohemoglobin. (05 Mar 2000) |
| carbocyclic compound | See: cyclic compound. (05 Mar 2000) |