P33 Determination of ferric sulfmyoglobin cyanide specie by resonance raman spectroscopy

Abstract

Upon the exposure of the human body to high H2S concentrations, in the presence of oxidizing agents like O2and H2O2, a sulfur atom is incorporated into the heme group of the hemoglobin (Hb) generating a sulfheme derivatives. This sulfHb derivative promotes a condition known as Sulfhemoglobinemia, which decreases the Hb ability to execute its function of oxygen transportation. Thus, to further comprehend the formation of Sulfhemoglobinemia, we need to understand the mechanism that leads to the modification of the heme group and its implications in the heme chemical structure and stability. Regarding this, horse heart myoglobin (Mb) was used as model to determine a suitable method to produce the ferric sulfmyoglobin cyanide complex (CN-sulfheme) as a way to define the structural change of the heme group induced by the formation of this derivative. The formation of CN-sulfMb species was attempted by two different methods. In the first method, H2O2(l) was added to a metMb sample and then 1 μL of H2S(l) solution was added to produce the ferric-sulfMb Complex. This was followed by the addition of 3 M KCN solution to generate the CN-sulfMb (FeIII) derivative. In the second method, O2(g) was used instead of H2O2(l). Each reaction was followed by UV–vis Spectroscopy in the 300–700 nm region. The addition of KCNto the sample demonstrates a shift of the Soret band from 407 nm to 422 nm attributed to the CN-sulfMb (FeIII) complex. The metCN-SulfMb structure was evaluated by Resonance Raman Spectroscopy. The data demonstrated satellites bands around v4 (1354 cm−1 and 1390 cm−1) attributed to the distortion of the heme group due to the incorporation of the sulfur ring [1] . Both methods generated the same results, but the metCN-SulfMb species generated by the presence of O2 is more stable than the analog species general by the presence of H2O2.