Biomaterial Database

Evidence of conformational changes in the non-equivalent binding sites of human serum transferrin. 1989

P J Marsden, and F A Smith, and R W Evans

Department of Medical Electronics and Physics, St Bartholomew's Medical College, London, England.

Samples of monoferric human serum transferrin have been prepared in which the iron occupies predominantly the N-site (sample A) and the C-site (sample B). 111In was then added in concentrations small enough to ensure that there was always an excess of specific binding sites. Because of the presence of apo-transferrin in both the samples, the occupancy by 111In in the two sites was only 75-78% C-site in sample A and only 61-65% N-site in sample B. Time differential PAC spectra showed a transition in the quadrupole frequency which took place at different temperatures, approximately 275 K in sample A and between 290 and 305 K in sample B. Debye and Arrhenius plots of the temperature dependence of the correlation time associated with molecular reorientation indicated an effective molecular volume about 50% larger than that of the hydrated diferric molecule determined by "biochemical" methods, and an activation energy for re-orientation of approximately 0.065 eV.

UI	MeSH Term	Description	Entries
D007205	Indium Radioisotopes	Unstable isotopes of indium that decay or disintegrate emitting radiation. In atoms with atomic weights 106-112, 113m, 114, and 116-124 are radioactive indium isotopes.	Radioisotopes, Indium
D007501	Iron	A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.	Iron-56,Iron 56
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
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
D013057	Spectrum Analysis	The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Spectroscopy,Analysis, Spectrum,Spectrometry
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic
D014168	Transferrin	An iron-binding beta1-globulin that is synthesized in the LIVER and secreted into the blood. It plays a central role in the transport of IRON throughout the circulation. A variety of transferrin isoforms exist in humans, including some that are considered markers for specific disease states.	Siderophilin,Isotransferrin,Monoferric Transferrins,Serotransferrin,Transferrin B,Transferrin C,beta 2-Transferrin,beta-1 Metal-Binding Globulin,tau-Transferrin,Globulin, beta-1 Metal-Binding,Metal-Binding Globulin, beta-1,Transferrins, Monoferric,beta 1 Metal Binding Globulin,beta 2 Transferrin,tau Transferrin
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