Interaction of p-benzoquinone with hemoglobin in smoker’s blood causes alteration of structure and loss of oxygen binding capacity

• Main Authors: Arunava Ghosh, Santanu Banerjee, Amrita Mitra, Monita Muralidharan, Bappaditya Roy, Rajat Banerjee, Amit Kumar Mandal, Indu B. Chatterjee
• Format: Article
• Language: English
• Published: Elsevier 2016-01-01
• Series: Toxicology Reports
• Online Access: http://www.sciencedirect.com/science/article/pii/S2214750016300142

Cigarette smoke (CS) is an important source of morbidity and early mortality worldwide. Besides causing various life-threatening diseases, CS is also known to cause hypoxia. Chronic hypoxia would induce early aging and premature death. Continuation of smoking during pregnancy is a known risk for the unborn child. Although carbon monoxide (CO) is considered to be a cause of hypoxia, the effect of other component(s) of CS on hypoxia is not known. Here we show by immunoblots and mass spectra analyses that in smoker’s blood p-benzoquinone (p-BQ) derived from CS forms covalent adducts with cysteine 93 residues in both the β chains of hemoglobin (Hb) producing Hb-p-BQ adducts. UV–vis spectra and CD spectra analyses show that upon complexation with p-BQ the structure of Hb is altered. Compared to nonsmoker’s Hb, the content of α-helix decreased significantly in smoker’s Hb (p = 0.0224). p-BQ also induces aggregation of smoker’s Hb as demonstrated by SDS-PAGE, dynamic light scattering and atomic force microscopy. Alteration of Hb structure in smoker’s blood is accompanied by reduced oxygen binding capacity. Our results provide the first proof that p-BQ is a cause of hypoxia in smokers. We also show that although both p-BQ and CO are responsible for causing hypoxia in smokers, exposure to CO further affects the function over and above that produced by Hb-p-BQ adduct. Keywords: p-Benzoquinone, Human smoker’s hemoglobin, Mass spectrometry, Atomic force microscopy, Oxygen binding capacity, CORM-3 [tricarbonylchloro(glycinato)ruthenium(II)]