Spectrophotometry of hemoglobin: a comparison of dog and man.

1. The absorptivity at 540 nm of hemiglobincyanide (epsilon 540HiCN) from dog blood was determined on the basis of iron and found to be within the range formerly obtained for human hemoglobin. 2. Consequently, epsilon 540HiCN = 11.0, the established value for human hemoglobin, may be used for dog hemoglobin. 3. On this basis the absorption spectra of oxyhemoglobin, de-oxygenated hemoglobin, carboxyhemoglobin, hemiglobin (methemoglobin) and hemiglobincyanide were determined for dog hemoglobin. 4. No significant differences were found between dog and human hemoglobin, except that dog hemiglobin binds less OH- as reflected in a difference between the absorption spectra of dog and human hemiglobin at the same pH.