See Also: albolabrin(medicine)

polymer (iou) and albolabrin (medicine)


polymer (iou)



polymer noun. M19.
[from Greek polumeres that has many parts, formed as POLY- + meros part, share.]
Chemistry. Orig., a substance whose formula is an exact multiple of that of another, composed of the same elements in the same proportions. Now usu., any substance which has a molecular structure built up largely or completely from a number (freq. very large) of similar polyatomic units bonded together; spec. any of the (mainly synthetic) organic compounds of this kind which form plastics, resins, rubbers, etc.
high polymer: see HIGH adjective.
Nature Natural rubber is still the preferred polymer for many high performance applications. Scientific American Glass is an inorganic polymer made up of rings and chains of repeating silicate units. attrib.: A. Toffler Suburban homes filled with specialists in..systems engineering, artificial intelligence, or polymer chemistry.
po'lymeride noun (now rare) = POLYMER M19.

albolabrin (medicine)


albolabrin -->
disintegrin
<protein> Peptides found in the venoms of various snakes of the viper family, that inhibit the function of some integrins of the _1 and _3 classes. They were first identified as inhibitors of platelet aggregation and were subsequently shown to bind with high affinity to integrins and to block the interaction of integrins with RGD containing proteins for example they block the binding of the platelet integrin _IIb_3 to fibrinogen. Disintegrins are effective inhibitors at molar concentrations 500-2000x lower than short RGDX peptides. They are cysteine rich peptides ranging from 45 to 84 amino acids in length and almost all of them have a conserved RGD sequence on a _ turn, presumed to be the site that binds to integrins. The assumption is that their biological role in the venom is to inhibit blood clotting. Found in many snake species, where they are called variously albolabrin, applagin, batroxostatin, bitistatin, echistatin, elegantin, flavouridin, halysin, kistrin, triflavin and trigramin.