Studies on the Oxidation - Reduction of Hemo

The apparently spontaneous conversion of hemoglobin to methemoglobin is an occurrence that has been recognized ever since the discovery of the latter blood pigment (Hoppe-Seyler, 1864). Although certain bacteria can oxidize hemoglobin to methemoglobin, the alteration of hemoglobin observed by the chemist is probably rarely due to bacterial action. Indeed, this conversion can occur in the complete absence of bacteria, taking place in blood drawn and held under aseptic conditions and in solutions of crystalline oxyhemoglobin sterilized by Berkefeld filtration. The so called "spontaneous" methemoglobin formation in drawn blood and in hemoglobin solutions seems to be the result of autoxidation of the hemoglobin itself or of other blood constituents. Some evidence indicative of the conditions influencing the "spontaneous" alteration of hemoglobin is presented in this paper. The investigation has consisted in large part of attempts to determine whether reducing conditions established by biological agents inhibit the transformation of hemoglobin to methemoglobin.