| Summary: | This thesis reports two separate kinetic studies on hemoproteins: the first, the oxidation of whale myoglobin, and the second, ligand binding and subunit aggregation kinetics of lamprey hemoglobin. The oxidation kinetics of sperm whale skeletal muscle oxymyoglobin by excess nitrite were studied. The oxidation curve showed an induction period prior to a rapid first order decay. The induction period varied inversely with the square of the nitrite concentration, whereas the rate of the first order decay was proportional to the nitrite concentration, but neither rate was affected by oxymyoglobin or metmyoglobin in the presence of excess nitrite. Various anions, such as cyanide, thiocyanate, azide and iodide, and some amino acids, such as tyrosine, tryptophan and cysteine, have inhibitory effects whereas other amino acids, such as histidine, methionine, threonine, and serine, have promotive effects on the rate of metmyoglobin formation. Intermediates were detected during the course of the oxidation. The extinction coefficients of one of the intermediates were estimated. The oxidation of deoxymyoglobin by excess nitrite showed a slower first order decay without the induction period and was not affected by dilute cyanide. The oxidation by nitrite of carboxymyoglobin, human oxyhemoglobin and its (beta)-chains, as well as Glycera monomeric oxyhemoglobin were studied for comparison with oxymyoglobin. The reaction of oxymyoglobin and nitrite is very complicated. The chain heterogeneity and subunit-subsunit interactions as well as dissociation of the tetramer cannot be the major causes of the sigmoidal nitrite oxidation kinetics. The kinetics of CO binding by the hemoglobin of the sea lamprey, Petromyzon marinus, have been followed in absorbance and light-scattering stopped-flow devices as well as by flash-photolysis. Lamprey hemoglobin is largely associated in the liganded form into monomers and is associated in the non-liganded form to dimers, and, at high concentration, tetramers. In order to describe the kinetics of ...
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