Biomaterial Database

The binding of thiopental to human serum albumin at variable pH and temperature. 1983

J H Christensen, and F Andreasen, and E B Jensen

The binding of thiopental was studied in vitro by equilibrium dialysis over the concentration range 0.8-80 micrograms/ml in solutions with 45 g albumin (HSA) per litre. The binding at 37 degrees was from 79% to 67.6% at pH 6 while it was 94.5% to 93.0% at pH 9. At intermediate values of pH the observed values for binding were compatible with the assumption of a gradual transition of an N-form of HSA present exclusively at pH 6 to a B-form present exclusively at pH 9. The variation in binding could not be explained by changes in the balance between ionised and nonionized drug (pKa = 7.6). An increase in r (number of thiopental molecules bound per HSA molecule) was demonstrated when the temperature was lowered to 2 degrees. Graphs showing the relation between drug concentrations and percentual binding all showed a very modest slope and it was concluded that a traditional binding model with calculation of the number of binding sites and association constants was of little use in the evaluation of our binding studies of thiopental. The binding between thiopental and albumin may be characterized best by the solubility of thiopental in hydrophobic areas in the albumin solutions.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D012709	Serum Albumin	A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.	Plasma Albumin,Albumin, Serum
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D013874	Thiopental	A barbiturate that is administered intravenously for the induction of general anesthesia or for the production of complete anesthesia of short duration.	Penthiobarbital,Thiomebumal,Thiopentobarbital,Bomathal,Nesdonal,Pentothal,Pentothal Sodico,Sodipental,Thionembutal,Thiopental Nycomed,Thiopental Sodium,Thiopentone,Tiobarbital Braun,Trapanal
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In