Proteins oxygen-binding

The most conspicuous use of iron in biological systems is in our blood, where the erythrocytes are filled with the oxygen-binding protein hemoglobin. The red color of blood is due to the iron atom bound to the heme group in hemoglobin. Similar heme-bound iron atoms are present in a number of proteins involved in electron-transfer reactions, notably cytochromes. A chemically more sophisticated use of iron is found in an enzyme, ribo nucleotide reductase, that catalyzes the conversion of ribonucleotides to deoxyribonucleotides, an important step in the synthesis of the building blocks of DNA. 

Mb Sperm whale myoglobin, an oxygen-binding protein 153 amino acid residues. Note that Mb lacks cysteine. 

The value Pso has been defined above for myoglobin as the pO that gives 50% saturation of the oxygen-binding protein with oxygen. Noting that at 50% saturation, F= (1 — F), then we have from Equation (A15.13). 

Senozan, N. et al. (1981) Hemocyanin of the giant keyhold limpet, Megathura crenulata. In Invertebrate Oxygen Binding Proteins Structure, Active Sites, andFunction (J. Lamy, and J. Lamy, eds.), pp. 703-717. Dekker, New York. 

The oxygen-binding protein hemerythrin exists as an octamer in equilibrium with its monomers ... 

The a- and P-subunits are structurally and evolutionarily related to each other and to myoglobin (Mb), the monomeric oxygen-binding protein in the muscles. 

The following are other recent reviews on the molecular and physical properties of this oxygen binding protein. 

Reversible Binding of a Protein to a Ligand Oxygen-Binding Proteins 158... 

Q Oxygen-Binding Proteins—Myoglobin Oxygen Storage... 

Oxygen-Binding Proteins—Hemoglobin Oxygen Transport... 

Porphyrin pathway This pathway creates very important molecules called porphyrins that are in turn used to make another molecule, called a heme, which can bind oxygen. Hemes are needed by oxygen-binding proteins like hemoglobin and myoglobin that transport or store oxygen. 

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