Biomaterial Database

Thyroxine binding to human serum albumin immobilized on sepharose and effects of nonprotein albumin-binding plasma constituents. 1990

K Kamikubo, and S Sakata, and S Nakamura, and T Komaki, and K Miura

Third Department of Internal Medicine, Gifu University School of Medicine, Japan.

125I-thyroxine (125I-T4) binding to human serum albumin (HSA) covalently attached onto CNBr-activated Sepharose (HSA-Sepharose) was studied. 125I-T4 binding to HSA-Sepharose was rapid and saturable. Nonlinear curve-fitting analysis of binding isotherms revealed two classes of binding sites. The values of dissociation constants of high and low affinity sites were 2.19 +/- 0.53 x 10(-6) M and 2.69 +/- 0.78 x 10(-5) M, respectively. The number of binding sites of the high and the low affinity sites were 1.28 +/- 0.46 mol/mol and 23.5 +/- 9.7 mol/mol of HSA, respectively. Fatty acids and bilirubin competitively inhibited the high-affinity binding of 125I-T4 to HSA-Sepharose without affecting the low-affinity binding. 8-anilino-1-naphthalene sulfonic acid (ANS) inhibited the high affinity T4 binding via reduction of the binding capacity. Unlabeled T4 showed little inhibition of ANS binding to HSA, as measured by fluorescence intensity. These results suggest that ANS allosterically inhibits the high-affinity T4 binding to HSA-Sepharose.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
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
D005227	Fatty Acids	Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)	Aliphatic Acid,Esterified Fatty Acid,Fatty Acid,Fatty Acids, Esterified,Fatty Acids, Saturated,Saturated Fatty Acid,Aliphatic Acids,Acid, Aliphatic,Acid, Esterified Fatty,Acid, Saturated Fatty,Esterified Fatty Acids,Fatty Acid, Esterified,Fatty Acid, Saturated,Saturated Fatty Acids
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000817	Anilino Naphthalenesulfonates	A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.	Naphthalenesulfonates, Anilino
D001663	Bilirubin	A bile pigment that is a degradation product of HEME.	Bilirubin IX alpha,Bilirubin, (15E)-Isomer,Bilirubin, (4E)-Isomer,Bilirubin, (4E,15E)-Isomer,Bilirubin, Calcium Salt,Bilirubin, Disodium Salt,Bilirubin, Monosodium Salt,Calcium Bilirubinate,Hematoidin,delta-Bilirubin,Bilirubinate, Calcium,Calcium Salt Bilirubin,Disodium Salt Bilirubin,Monosodium Salt Bilirubin,Salt Bilirubin, Calcium,delta Bilirubin
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D012685	Sepharose		Agarose,Sepharose 4B,Sepharose C1 4B,4B, Sepharose C1,C1 4B, Sepharose
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