Effect of pH on the kinetics of oxygen and carbon monoxide reactions with hemoglobin from the air-breathing fish, Loricariichthys

Abstract

1. 1. Loricariichthys sp., an air-breathing fish from the Amazon River has one major hemoglobin component. 2. 2. Quantitative studies on the kinetics of O2 dissociation and CO combination to the protein were performed by stopped-flow experiments at different pH values and a constant ATP concentration of 1.25 mM. 3. 3. The oxygen dissociation shows a simple first order behavior and a strong pH dependence. 4. 4. The CO combination kinetics, on the other hand, were homogeneous and fast at higher pH values and slow and clearly autocatalytic at pH values below 7.0. © 1979.