Receptor destroying activity

Herceptin attaches to the HER2/neu receptor and activates the complement system (a series of serum and cell-associated proteins involved in immune response) to destroy those cells expressing such receptors. Through this action, Herceptin disrupts the signaling pathway for breast cancer cell proliferation (refer to diagram below). 

Because of the NA receptor-destroying enzyme activity, the sites of viral proteins on the cell surface are devoid of terminal sialic acid residues. Desialation is necessary to prevent aggr ation of the progeny virions, which greatly decreases infectivity. 

JA is also effective [79]. The structural requirements are similar, but unlike JA activity, reduction of the 9,10 double bond destroys activity, so that a different receptor is indicated [84]. Replacement of the carboxyl with either hydroxyl or hydrogen gives rise to molecules whieh are competitive inhibitors of tuber-inducing activity [84]. Again, these conclusions are provisional until ehiral analogues are tested. 

After the olfactory receptor is activated, the semiochemical signal must be destroyed to prevent continued stimulation. Esterase, dehydrogenase, aldehyde oxidase, epoxidase, and glutathione-S-transferase activities have all been detected in the sensillum and could degrade the signal. A further example is found in the pale-brown chafer. Phyllopertha diversa. which uses 1,3-dimethyl-2,4-( liT,3//)-quinazolinedione 10 as its sex pheromone. 

Sialic acid was the first virus receptor identified. Hirst and McClelland and Hare discovered that influenza virus is able to hemagglutinate and that adsorbed virus is eluted from erythrocytes on incubation at 37°C, indicating an enzymatic destruction of a receptor substance on the cells [1, 2]. When a similar enzymatic activity was subsequently detected in Vibrio cholerae cultures, the term receptor-destroying enzyme was introduced [3]. The substance released by the viral enzyme from soluble hemagglutination inhibitors was initially characterized as a carbohydrate of low molecular weight [4] and then identified in crystalline form as A-acetyl-o-neuraminic acid [5]. Thus, it was clear that the receptor determinant of influenza virus was sialic acid and that the viral enzyme was a neuraminidase. Furthermore, for the first time an important biological function of sialic acid had been identified. 

Kristiansen M, Froystad MK, Rishovd AL, Gjoen T (2002) Characterization of the receptor-destroying enzyme activity from infectious salmon anaemia vims. J Gen Virol 83 2693-2697... 

Schultze B, Wahn K, Klenk HD, Herrler G (1991) Isolated HE-protein from hemagglu-tinating encephalomyelitis virus and bovine coronavirus has receptor-destroying and receptor-binding activity. Virology 180 221-228... 

Vlasak R, Luytjes W, Leider J, Spaan W, Palese P (1988) The E3 protein of bovine coronavirus is a receptor-destroying enzyme with acetylesterase activity. J Virol 62 4686 690... 

Storz J, Zhang XM, Rott R (1992) Comparison of hemagglutinating, receptor-destroying, and acetylesterase activities of avinilent and virulent bovine coronavirus strains. Arch Virol 125 193-204... 

Vlasak R, Krystal M, Nacht M, Palese P (1987) The influenza c virus glycoprotein (HE) exhibits receptor-binding (hemagglutinin) and receptor-destroying (esterase) activities. Virology 160 419-425... 

The receptor for influenza C is assumed to be 9-0-acetyl sialic acid, based on the esterase activity of its receptor-destroying enzyme [10]. In vivo, 9-O-acetyl sialic acids are added selectively to glycoproteins and glycolipids in a limited range of cell types, although these cell types are reasonably widely distributed [11], including mucosal epithelia. A putative receptor protein, a 40 kDa mucin heavily modified by 9-O-acetyl sialic acid, is present on apical surfaces of permissive MDCK cells and is rapidly and constitutively endocytosed [12],... 

Working in a different area. Hirst (1941) as well as McClelland and Hare (1941) found that chicken red blood cells could be agglutinated by influenza virus. Burnet (1948) later found that mucins (mucoproteins) could inhibit this process and subsequently found that an enzyme from Vibrio cholerae could destroy this inhibitory activity. This enzyme was called RDE (receptor destroying enzyme) because it could also destroy the ability of red blood cells to absorb influenza virus. 

---