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Can gas replace protein function? CO abrogates the oxidative toxicity of myoglobin.

Sher EA, Sholto AY, Shaklai M, Shaklai N - PLoS ONE (2014)

Bottom Line: The main cause of LDL oxidation by Hb was found to be hemin which readily transfers from Hb to LDL.These reactions were fully arrested by CO.The data are interpreted to suit several circumstances, some physiological, such as high muscle activity, and some pathological, such as rhabdomyolysis, ischemia/reperfusion and skeletal muscle disuse atrophy.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.

ABSTRACT
Outside their cellular environments, hemoglobin (Hb) and myoglobin (Mb) are known to wreak oxidative damage. Using haptoglobin (Hp) and hemopexin (Hx) the body defends itself against cell-free Hb, yet mechanisms of protection against oxidative harm from Mb are unclear. Mb may be implicated in oxidative damage both within the myocyte and in circulation following rhabdomyolysis. Data from the literature correlate rhabdomyolysis with the induction of Heme Oxygenase-1 (HO-1), suggesting that either the enzyme or its reaction products are involved in oxidative protection. We hypothesized that carbon monoxide (CO), a product, might attenuate Mb damage, especially since CO is a specific ligand for heme iron. Low density lipoprotein (LDL) was chosen as a substrate in circulation and myosin (My) as a myocyte component. Using oxidation targets, LDL and My, the study compared the antioxidant potential of CO in Mb-mediated oxidation with the antioxidant potential of Hp in Hb-mediated oxidation. The main cause of LDL oxidation by Hb was found to be hemin which readily transfers from Hb to LDL. Hp prevented heme transfer by sequestering hemin within the Hp-Hb complex. Hemin barely transferred from Mb to LDL, and oxidation appeared to stem from heme iron redox in the intact Mb. My underwent oxidative crosslinking by Mb both in air and under N2. These reactions were fully arrested by CO. The data are interpreted to suit several circumstances, some physiological, such as high muscle activity, and some pathological, such as rhabdomyolysis, ischemia/reperfusion and skeletal muscle disuse atrophy. It appear that CO from HO-1 attenuates damage by temporarily binding to deoxy-Mb, until free oxygen exchanges with CO to restore the equilibrium.

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CO attenuates Hb-induced LDL oxidation.LDL oxidation kinetics was traced in reaction mixtures containing ferric-Hb (3 µM), nLDL or dLDL (100 µg protein/ml) and H2O2 (3 µM) at anaerobic conditions of N2 or CO. Protein oxidation was followed by formation of conjugated dienes. Reactions rate is shown as ΔOD since the proteins (LDL and Hb) contribute to light absorption in UV region (ΔOD = OD(tx)−OD(t0) ). A representative result of 3 independent experiments is shown.
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pone-0104075-g004: CO attenuates Hb-induced LDL oxidation.LDL oxidation kinetics was traced in reaction mixtures containing ferric-Hb (3 µM), nLDL or dLDL (100 µg protein/ml) and H2O2 (3 µM) at anaerobic conditions of N2 or CO. Protein oxidation was followed by formation of conjugated dienes. Reactions rate is shown as ΔOD since the proteins (LDL and Hb) contribute to light absorption in UV region (ΔOD = OD(tx)−OD(t0) ). A representative result of 3 independent experiments is shown.

Mentions: LDL oxidation kinetics was traced in reaction mixtures containing ferric-Hb, LDL, and hydrogen peroxide. Air was replaced with either N2 or CO. Protein oxidation was observed by the formation of conjugated dienes at 268 nm. Fig. 4 shows that the rates of Hb-induced oxidation in the presence of CO were reduced dramatically. Oxidation under CO proceeded more slowly. Suppression of oxidation by CO also occurred when the freshly prepared LDL was replaced by dLDL, although to a lesser extent.


Can gas replace protein function? CO abrogates the oxidative toxicity of myoglobin.

Sher EA, Sholto AY, Shaklai M, Shaklai N - PLoS ONE (2014)

CO attenuates Hb-induced LDL oxidation.LDL oxidation kinetics was traced in reaction mixtures containing ferric-Hb (3 µM), nLDL or dLDL (100 µg protein/ml) and H2O2 (3 µM) at anaerobic conditions of N2 or CO. Protein oxidation was followed by formation of conjugated dienes. Reactions rate is shown as ΔOD since the proteins (LDL and Hb) contribute to light absorption in UV region (ΔOD = OD(tx)−OD(t0) ). A representative result of 3 independent experiments is shown.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128816&req=5

pone-0104075-g004: CO attenuates Hb-induced LDL oxidation.LDL oxidation kinetics was traced in reaction mixtures containing ferric-Hb (3 µM), nLDL or dLDL (100 µg protein/ml) and H2O2 (3 µM) at anaerobic conditions of N2 or CO. Protein oxidation was followed by formation of conjugated dienes. Reactions rate is shown as ΔOD since the proteins (LDL and Hb) contribute to light absorption in UV region (ΔOD = OD(tx)−OD(t0) ). A representative result of 3 independent experiments is shown.
Mentions: LDL oxidation kinetics was traced in reaction mixtures containing ferric-Hb, LDL, and hydrogen peroxide. Air was replaced with either N2 or CO. Protein oxidation was observed by the formation of conjugated dienes at 268 nm. Fig. 4 shows that the rates of Hb-induced oxidation in the presence of CO were reduced dramatically. Oxidation under CO proceeded more slowly. Suppression of oxidation by CO also occurred when the freshly prepared LDL was replaced by dLDL, although to a lesser extent.

Bottom Line: The main cause of LDL oxidation by Hb was found to be hemin which readily transfers from Hb to LDL.These reactions were fully arrested by CO.The data are interpreted to suit several circumstances, some physiological, such as high muscle activity, and some pathological, such as rhabdomyolysis, ischemia/reperfusion and skeletal muscle disuse atrophy.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.

ABSTRACT
Outside their cellular environments, hemoglobin (Hb) and myoglobin (Mb) are known to wreak oxidative damage. Using haptoglobin (Hp) and hemopexin (Hx) the body defends itself against cell-free Hb, yet mechanisms of protection against oxidative harm from Mb are unclear. Mb may be implicated in oxidative damage both within the myocyte and in circulation following rhabdomyolysis. Data from the literature correlate rhabdomyolysis with the induction of Heme Oxygenase-1 (HO-1), suggesting that either the enzyme or its reaction products are involved in oxidative protection. We hypothesized that carbon monoxide (CO), a product, might attenuate Mb damage, especially since CO is a specific ligand for heme iron. Low density lipoprotein (LDL) was chosen as a substrate in circulation and myosin (My) as a myocyte component. Using oxidation targets, LDL and My, the study compared the antioxidant potential of CO in Mb-mediated oxidation with the antioxidant potential of Hp in Hb-mediated oxidation. The main cause of LDL oxidation by Hb was found to be hemin which readily transfers from Hb to LDL. Hp prevented heme transfer by sequestering hemin within the Hp-Hb complex. Hemin barely transferred from Mb to LDL, and oxidation appeared to stem from heme iron redox in the intact Mb. My underwent oxidative crosslinking by Mb both in air and under N2. These reactions were fully arrested by CO. The data are interpreted to suit several circumstances, some physiological, such as high muscle activity, and some pathological, such as rhabdomyolysis, ischemia/reperfusion and skeletal muscle disuse atrophy. It appear that CO from HO-1 attenuates damage by temporarily binding to deoxy-Mb, until free oxygen exchanges with CO to restore the equilibrium.

Show MeSH
Related in: MedlinePlus