Biomaterial Database

Myoglobin interspecies structural differences: effects on autoxidation and oxygenation. 1986

D J Livingston, and D A Watts, and W D Brown

Thermodynamic and kinetic parameters of the oxygenation and autoxidation reactions were determined for yellowfin tuna (Thunnus albacares), Pacific green sea turtle (Chelonia mydas caranigra), and sperm whale myoglobin. These proteins have quite similar heme contact residues, but vary in residues which are involved in globin stabilization and in postulated ligand paths to the heme iron. Oxygen equilibria measurements from 10 to 40 degrees C reveal that green sea turtle myoglobin has a lower oxygen affinity and lower enthalpy and entropy for oxygen-binding than the other proteins. Yellowfin tuna myoglobin has the most rapid oxygen dissociation rate and the highest susceptibility to autoxidation under all conditions studied. However, the dependence of the autoxidation rate on ionic strength is the same for the three proteins, despite substantial differences in their dynamic stabilities. These results suggest that the autoxidation reaction is more dependent on ligand accessibility than on the dynamic stability of the myoglobin.

UI	MeSH Term	Description	Entries
D009211	Myoglobin	A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
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
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D005399	Fishes	A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.
D006418	Heme	The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.	Ferroprotoporphyrin,Protoheme,Haem,Heme b,Protoheme IX
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
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
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