Biomaterial Database

Fluoride binding to the cytochrome c ferric heme octapeptide. A model for anion binding to the active site of high spin ferric heme proteins. 1981

Y P Huang, and R J Kassner

The temperature dependence of the magnetic susceptibility of the ferric hemeoctapeptide from cytochrome c was measured in the presence and absence of fluoride ion to study the fluoride binding equilibrium of the hemeoctapeptide. The shift in the 1H NMR signal of sodium 4,4-dimethyl-4-silapentanesulfonate caused by the hemeoctapeptide was measured from -11 to 80 degrees C in a D2O/ethylene glycol solution. Magnetic susceptibilities obtained from the shifts were used to calculate the binding constant at each temperature. The equilibrium constant is 0.95 M-1 at 25 degrees C. Thermodynamic values determined from a plot of ln K versus 1/T are delta H0 = 19,700 J/mol (4,700 cal/mol) and delta S0 = 66.1 J/K mol (15.8 entropy units). The equilibrium and thermodynamic values are compared with those for fluoride binding to hemeproteins and with values for azide and cyanide binding to the hemeoctapeptide and hemoproteins. The differential binding data are used to assess the proposed bonded and nonbonded interactions between the distal histidine and the protein on the axial anionic ligand affinity. The results suggest that bonded interactions between the distal histidine and the ligand may contribute considerable stabilization to the hemoprotein-ligand complex.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D009682	Magnetic Resonance Spectroscopy	Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).	In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D010544	Peroxidases		Ovoperoxidase
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
D005459	Fluorides	Inorganic salts of hydrofluoric acid, HF, in which the fluorine atom is in the -1 oxidation state. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Sodium and stannous salts are commonly used in dentifrices.	Fluoride
D006420	Hemeproteins	Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)	Hemeprotein,Heme Protein,Heme Proteins,Protein, Heme,Proteins, Heme
D006736	Horses	Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.	Equus caballus,Equus przewalskii,Horse, Domestic,Domestic Horse,Domestic Horses,Horse,Horses, Domestic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia