Acidic glycoprotein

ACRYLIC ESTERPOLYTffiRS - 2-CYANOACRYLIC ESTERPOLYTffiRS] (Vol 1) Alphal-acid glycoprotein... 

Properties and Structure. a -Acid glycoprotein (a -AGP) has a molecular mass of about 41,000 and consists of a peptide chain having 181 amino acid residues and five carbohydrate units (14,15). Two cystine disulfide cross-linkages connect residues 5 and 147 and residues 72 and 164. The carbohydrate units comprise 45% of the molecule and contain siaUc acid, hexosamine, and neutral hexoses. In phosphate buffer the isoelectric point of the... 

EoUowing po administration moricizine is completely absorbed from the GI tract. The dmg undergoes considerable first-pass hepatic metabolism so that only 30—40% of the dose is bioavailable. Moricizine is extensively (95%) bound to plasma protein, mainly albumin and a -acid glycoprotein. The time to peak plasma concentrations is 0.42—3.90 h. Therapeutic concentrations are 0.06—3.00 ]l/niL. Using radiolabeled moricizine, more than 30 metabolites have been noted but only 12 have been identified. Eight appear in urine. The sulfoxide metabolite is equipotent to the parent compound as an antiarrhythmic. Elimination half-life is 2—6 h for the unchanged dmg and known metabolites, and 84 h for total radioactivity of the labeled dmg (1,2). 

Absorption after po dosing is fairly complete. It undergoes extensive first-pass metaboHsm in the Hver and is 60% bioavailable. It is extensively bound (99%) to a -acid glycoproteins. Bepridil is almost completely metaboli2ed in the Hver. Seventeen metaboHtes have been identified but only the 4-hydroxy-A/-phenyl-bepridil has some pharmacological activity. The elimination half-life is 33—42 h (107). 

LC-MS with on-line SPE using a RAM pre-column with an internal ODS phase was described by van der Hoeven et al. (95) for the analysis of cortisol and prednisolone in plasma, and arachidonic acid in urine. The samples were injected directly and the only off-line pretreatment required was centrifugation. By using the on-line SPE-LC-MS system, cortisol and related compounds could be totally recovered and quantified in 100 p.1 plasma within 5 min with a typical detection of 2 ng/ml (Figure 11.6(b)). The RAM-type of sorbents, in which the outer surface of the particles is covered with aj-acid glycoprotein, also appear to be useful for direct SPE of... 

Proteins. A chiral stationary phase with immobilized a -acid glycoprotein on silica beads was introduced by Hermansson in 1983 [18, 19]. Several other proteins such as chicken egg albumin (ovalbumin), human serum albumin, and cellohy-drolase were also used later for the preparation of commercial CSPs. Their selectivity is believed to occur as a result of excess of dispersive forces acting on the more retained enantiomer [17]. These separation media often exhibit only modest loading capacity. 

Chiral-AGP alpha-acid glycoprotein bonded to silica. 

CRP , complement , PLA2 , serum amyloid A , fibrinogen , c -acid glycoprotein , IL-1Ra , ceruloplasmin , ai-antichymotrypsin , LBP albumin , haptoglobin , IGF-1 , transferrin , u2-HS glycoprotein ... 

Jones K, Hoggard PC, Khoo S, Maher B, Back DJ (2001) Effect of alphal-acid glycoprotein on the intracellular accumulation of the HIV protease inhibitors saquinavir, ritonavir and indinavir in vitro, Br J Chn Pharmacol 51 99-102... 

These proteins are called acute phase proteins (or reactants) and include C-reactive protein (CRP, so-named because it reacts with the C polysaccharide of pneumococci), ai-antitrypsin, haptoglobin, aj-acid glycoprotein, and fibrinogen. The elevations of the levels of these proteins vary from as little as 50% to as much as 1000-fold in the case of CRP. Their levels are also usually elevated during chronic inflammatory states and in patients with cancer. These proteins are believed to play a role in the body s response to inflammation. For example, C-reactive protein can stimulate the classic complement pathway, and ai-antitrypsin can neutralize certain proteases released during the acute inflammatory state. CRP is used as a marker of tissue injury, infection, and inflammation, and there is considerable interest in its use as a predictor of certain types of cardiovascular conditions secondary to atherosclerosis. Interleukin-1 (IL-1), a polypeptide released from mononuclear phagocytic cells, is the principal—but not the sole—stimulator of the synthesis of the majority of acute phase reactants by hepatocytes. Additional molecules such as IL-6 are involved, and they as well as IL-1 appear to work at the level of gene transcription. 

Acute phase response proteins (eg, C-reactive protein, a,-acid glycoprotein [orosomucoid])... 

Bovine serum albumin covalently bonded to silica and a-acid glycoprotein immobilized on silica have been used to resolve a wide range of acidic and basic drugs and amino acid derivatives [807-810]. Because of their complex structures, however, the... 

There is a wide variety of commercially available chiral stationary phases and mobile phase additives.32 34 Preparative scale separations have been performed on the gram scale.32 Many stationary phases are based on chiral polymers such as cellulose or methacrylate, proteins such as human serum albumin or acid glycoprotein, Pirkle-type phases (often based on amino acids), or cyclodextrins. A typical application of a Pirkle phase column was the use of a N-(3,5-dinitrobenzyl)-a-amino phosphonate to synthesize several functionalized chiral stationary phases to separate enantiomers of... 

Acid glycoprotein has also been found in-tracellularly and exists as a membrane-bound form... 

F. Bree, G. Houin, J. Barre, J. L. Moretti, V. Wirquin, and J.-P. Tillement, Pharmacokinetics of intravenously administered 125I-labelled human alpha-1-acid glycoprotein, Clin. Pharmacokinet, 11, 336-342 (1986). 

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