Variability of the magnetic moment of carbon monoxide hemoglobin from carp.

Deionized carp carbon monoxide hemoglobin in distilled water or in bis(2-hydroxyethyl)imino-tris(hydroxymethyl)methane or Tris buffer exhibits a slight but significant paramagnetism. This is most clearly demonstrated by the decrease in this paramagnetism that is caused by the addition of inositol hexaphosphate to this protein in the former buffer at pH 6.3-6.4. No such effect is seen when inositol hexaphosphate is added to carp cyanomethemoglobin, demonstrating that the change observed with carbon monoxide derivative is not due to a modification in the diamagnetic properties of the protein.