Figure 6.

Absorbance of solution of containing 100% methemoglobin mixed with PBS (black lines) or mixed with a solution containing 100 μM NaHS in PBS (red lines) (A). The same reactions were studied with a solution containing 50% hemoglobin-50% methemoglobin (B). 100% hemoglobin (C), and 100% hemoglobin with MB alone (D, green line) or with H₂S (100 μM) plus MB (60 μM) (D, blue line). Note that the addition of MB allowed the formation of a new peak of absorbance, reflecting the creation of a combined pool of H₂S on hemoglobin.