A 1 -acid glycoprotein, AGP

A Amini, C Pettersson, D Westerlund. Enantioresolution of disopyramide by capillary affinity electrokinetic chromatography with human a,-acid glycoprotein (AGP) as chiral selector applying a partial-filling technique. Electrophoresis 18 950-957, 1997. 

Proteins have also been used as CMPAs for chiral resolution by liquid chromatography. Bovine serum albumin (BSA) and a]-acid glycoproteins (AGP) were investigated as CMPAs. Allenmark et al. [87] used BSA protein as the CMPA for... 

A number of proteins are commercially available as CSPs including a-acid glycoproteins (AGP, the major plasma binding protein for basic drugs), human serum albumin (HSA, the major plasma binding protein for weakly acidic drugs), bovine serum albumin (BSA), ovomucoid (OVM), and cellobiohydro-lase (CBH) [12]. The proteins are bonded to silica and utilized in reversed-phase mode with an aqueous buffer/organic modifier eluent. Mobile-phase... 

The whole sample was then injected onto the chiral column, 10 cm long, 4.0 mm I.D., packed with silica gel particles, 5 pm in diameter, bonded with a,-acid glycoprotein (AGP). The results obtained are shown in figure 11.2. The separation ratio between the enantiomer pair is 1.23. Chromatogram (A) is the separation of a 50 ng sample of the racemic pair. Chromatogram (B) is from a blood serum sample taken 4 hours after the oral administration of 120 mg of racemic Verapamil. Chromatogram (C) is from a blood serum sample taken 15 min after the intravenous infusion of 15 mg of racemic Verapamil. It is clear that this type of analysis will allow an accurate pharmokinetic study of the relative biochemical degradation or excretion of the two enantiomers. 

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... 

Finally, nucleolin has also been identified as a repressor of polymerase II transcription (Yang et al 1994). Biochemical and functional studies further established that nucleolin is a transcription repressor for regulation of alpha-1 acid glycoprotein (AGP)... 

Imre, T., Schlosser, G., Pocsfalvi, G., Sicihano, R., Mobiar-SzoUosi, E., Kremmer, T., Malorni, A., and Vekey, K., Glycosylation site analysis of human alpha-l-acid glycoprotein (AGP) by capillary liquid chromatography-electrospray mass spectrometry. Journal of Mass Spectrometry 40(11), 1472-1483, 2005. 

A simplified equilibrium extraction model (Fig. 6) was presented by Dordick and colleagues [188] to explain the resolution behavior of glycoproteins in affinity based reverse micellar extraction and separation (ARMES). Their system for the study includes soybean peroxidase (SBP, MW 37 KDa, pi 4.1) and aj-acid glycoprotein (AGP, MW 43 KDa, pi 3.7) as glycoprotein solutes, concanavalin A (ConA) as the affinity ligand in AOT/isooctane RMs. The separation factor (a) for the separation of SBP from AGP can be given by... 

Work by Haston et al. (2002) also indicates that acidic glycoprotein (AGP) influences Type II collagen fibrillogenesis, where in vitro studies show that low concentrations of AGP produced decreases in fibrillogenesis rate and fibril diameter. High concentrations produced fibrils at a rate and diameter dependent on fucosylation of AGP. Highly fucosylated AGP produced narrow fibrils, and poorly fucosylated AGP produced thicker fibrils. 

Li and Lloyd were among the first to report the use of immobilized proteins as a CSP in CEC [141]. They packed silica particles derivatized with ar acid glycoprotein (AGP) into CE capillaries. Chiral sites are present in the peptide sequence of AGP, as well as in the carbohydrate units present. The presence of the chiral centers sets up the same type of diastereomeric interactions as with CDs, as well as a host of other interactions such as hydrogen bonding. At the... 

Bathory, G., Meszaros, G., Gergely, A. Study on the sorption properties of al-acid glycoprotein (AGP)-based stationary phase modified by organic solvents. Chirality, 2003,15, 377-381. 

Because so few type V CSPs have well established molecular structures, most scientists are forced to use a series of probe molecules and some sort of regression analysis to divulge pertinent information about the mechanism of chiral recognition. For example, Norinder and Hermansson [85] separated thirty-five N-aminoalkylsuc-cinimides, 36, on an ai-acid glycoprotein (AGP) column. 

Recently, a new polyacrylamide (PAA) derivative that allows dynamic coating (UltraTrol LN- Target Discovery, Palo Alto, CA) has been reported for the efficient separation of glycoforms of ATT [70], A comparison of the ability of PB and UltraTrol LN for the separation of bovine alpha-1-acid glycoprotein (AGP), bovine serum fetuin (BSF), and rhEPO sialoforms and their application coupling with MS has been reported [30,71]. Better resolution of sialoforms was obtained with capillaries coated with UltraTrol-LN in acidic volatile buffers used for coupling CE to ESI-TOF MS. 

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