Introduction: Hemorrhage is a leading cause of death in trauma patients. Interventions dedicated to hemostatic resuscitation have demonstrated benefit in decreasing mortality due to hemorrhagic injury. There remain significant limitations to donor-based blood transfusions. We have identified a heme-binding protein, the Bacterial Regulator of carbon monoxide metabolism (RcoM), with suitable properties to be a robust artificial oxygen carrier. We have engineered a variant that lacks a DNA binding domain and contains cysteine mutations for improved stability (RcoM HBD-CCC). Hypothesis: We hypothesize that engineered RcoM HBD-CCC can be used as an ideal artificial oxygen carrier due to the optimization of 4 factors: ligand binding, nitrite reduction rate, autoxidation rate, and thermal denaturation. Methods: Spectrophotometric methods were used to characterize RcoM HBD-CCC in terms of its biochemical properties for optimal oxygen transport and release. Specifically, ligand binding was tested by determination of the P50 (oxygen pressure for 50% saturation of the molecule) value indicating the affinity of RcoM HBD-CCC towards oxygen. Nitrite reduction assays were carried out to test the rate at which nitric oxide (NO) forms to counteract potential NO scavenging. The autoxidation rate determines how long a protein stays in the reduced state, where it is able to bind to oxygen. Thermal denaturation (T m ) identifies the resistance of a protein to higher temperatures. Results: We determined that RcoM HBD-CCC’s P50 value was 4.2 mmHg which is within the ideal range for oxygen binding affinity given that optimal values for oxygen carriers to mimic hemoglobin oxygen dissociation are between 1 to 26 mmHg. Nitrite reductase rate was 5.6M -1 s -1 which is well above the rate for Hb (K = 0.12 M -1 s -1 ). RcoM HBD-CCC has a low autoxidation rate at 0.016 min -1 . RcoM HBD-CCC has a T m of 71°C which is well above all ambient environmental temperatures. Conclusion: We have designed and synthesized a variant of RcoM that we have demonstrated in in vitro spectrophotometric assays to have ideal biochemical properties for an artificial oxygen carrier. We next plan to test the efficacy of RcoM HBD-CCC in animal models of hemorrhage and assess safety in animal exposure models.