Effect of pH, ADP and muscle soluble components on cod hemoglobin characteristics and extractability

The effect of pH, ADP and the soluble components of the muscle on the extractability of cod hemoglobin was studied. A marked decrease in hemoglobin extractability from washed and unwashed mince was observed at pH 6.0. This coincided with the binding of the hemoglobin to cod sarcoplasmic reticulum at pH 6.0. After 10 min of incubation at pH 6.0, most non-extractable hemoglobin could be extracted at pH 7.0 or higher. The soluble fraction of cod muscle increased hemoglobin extractability and decreased the hemoglobin bound to the sarcoplasmic reticulum. A decrease in hemoglobin extractability in unwashed mince with added ADP at pH 7.0 occurred with an increased amount of deoxyhemoglobin. The results suggested that medium pH and deoxygenation of hemoglobin were related to the decrease in hemoglobin extractability at pH 6.0.