Binding of prazosin to alpha 1-acid glycoprotein and albumin: effect of protein purity and concentrations.

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Sager G, Jaeger R, Little C

Binding of prazosin to alpha 1-acid glycoprotein and albumin: effect of protein purity and concentrations.

Pharmacol Toxicol. 1989 Apr;64(4):365-8.

PubMed ID

2748545 [ View in PubMed

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Abstract

Prazosin is extensively bound in human serum/plasma. In the present study a bound fraction of 93-95% was observed at 37 degrees for therapeutic drug concentrations. Both alpha 1-acid glycoprotein (AAG) and albumin (HSA) are established as transport proteins for prazosin, but their individual contribution to the extent and variability of protein binding in serum/plasma is unclear. The present study showed that AAG possesses one binding site per molecule with high affinity (Kd approximately 0.8 microM) for prazosin. HSA, essentially globulin-free, bound prazosin with lower affinity (Kd approximately 30 microM) with an average of 0.3 binding sites per molecule. However, less purified HSA, containing globulins, exhibited apparently higher affinity (Kd approximately 8 microM), but lower binding capacity (0.07 sites per molecule) for prazosin. In mixtures of highly purified proteins, the concentrations of AAG, and not HSA, determined the extent and variability of prazosin binding.

DrugBank Data that Cites this Article

Drug Carriers

Drug	Carrier	Kind	Organism	Pharmacological Action	Actions
Prazosin	Alpha-1-acid glycoprotein 1	Protein	Humans	No	Substrate	Details