title: The binding of physostigmine to human serum albumin.
abstract: The binding of [3H]physostigmine to crystallized human serum albumin (HSA) has been investigated using equilibrium dialysis. The percentage bound to 1% (w/v) HSA decreased from 18 to 4% as the total concentration of physostigmine increased from 3.3 nM to 2.7 microM (0.9 to 750 ng mL-1). A single class of specific binding sites with a large affinity constant, K = 8 x 10(7) L mol-1, was identified. The concentration of binding sites was approximately 3 nM. The Michaelis constants for human serum cholinesterase and albumin were the same; an explanation for these results is that the drug is binding to a trace cholinesterase, in the albumin.
authors.affiliation: Department of Pharmacology, London Hospital Medical College UK.
authors.forename: R
authors.initials: R
authors.lastname: Whelpton
authors.forename: P R
authors.initials: PR
authors.lastname: Hurst
mesh_terms: D001665:Binding Sites; D002802:Cholinesterases / Q000097:blood / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007700:Kinetics; D010830:Physostigmine / Q000097:blood / Q000378:metabolism*; D012709:Serum Albumin / Q000378:metabolism*
chemical_list: D012709:Serum Albumin; D010830:Physostigmine; D002802:Cholinesterases