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Evaluating the capacity to generate and preserve nitric oxide bioactivity in highly purified earthworm erythrocruorin: a giant polymeric hemoglobin with potential blood substitute properties.

Roche CJ, Talwar A, Palmer AF, Cabrales P, Gerfen G, Friedman JM - J. Biol. Chem. (2014)

Bottom Line: A potentially important additional property is the capacity of the HBOC either to generate nitric oxide (NO) or to preserve NO bioactivity to compensate for decreased levels of NO in the circulation.The results show that LtHb undergoes the same reactions as HbA and that the reduced efficacy for these reactions for LtHb relative to HbA is consistent with the much higher redox potential of LtHb.Evidence of functional heterogeneity in LtHb is explained in terms of the large difference in the redox potential of the isolated subunits.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461.

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A comparison between HbA (traces A) and LtHb (traces B) of the rate of nitrite reductase at pH 7.0 monitored as the decay of the 430 nm Sôret band as a function of the nitrite to heme ratio: 1:1 (a), 2:1 (b), and 5:1 (c). The heme concentration in all cases was ∼0.20 mm. The red lines represent fits to the data using Origin 8.5 as described under “Experimental Procedures.” The traces were all normalized to better expose the comparison of the kinetics.
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Figure 1: A comparison between HbA (traces A) and LtHb (traces B) of the rate of nitrite reductase at pH 7.0 monitored as the decay of the 430 nm Sôret band as a function of the nitrite to heme ratio: 1:1 (a), 2:1 (b), and 5:1 (c). The heme concentration in all cases was ∼0.20 mm. The red lines represent fits to the data using Origin 8.5 as described under “Experimental Procedures.” The traces were all normalized to better expose the comparison of the kinetics.

Mentions: Fig. 1 shows a comparison between HbA and LtHb with respect to the normalized nitrite-induced decay of the deoxyheme population as a function of the ratio of added nitrite to heme while keeping the heme concentrations relatively fixed. It can be seen that at all ratios of nitrite to heme LtHb appears to exhibit two distinct phases, whereas under these conditions only one phase is observed for HbA. Exponential rates were calculated using both single and double exponential fitting algorithms associated with the program in Origin 8.5 (y = y0 + Ae−kt or y = y0 + A1e−kt1 + A2e−kt2). For HbA, a single exponential algorithm fit extremely well; however, for LtHb, the single exponential fit was poor, whereas the double exponential fit was much better. The goodness of fit for each of the kinetic curves was determined by comparing both the R2 value and the χ2 value for each equation used. Fits were chosen that had R2 values closest to 1 (0.97–0.99) or χ2 values of 10−4 or less.


Evaluating the capacity to generate and preserve nitric oxide bioactivity in highly purified earthworm erythrocruorin: a giant polymeric hemoglobin with potential blood substitute properties.

Roche CJ, Talwar A, Palmer AF, Cabrales P, Gerfen G, Friedman JM - J. Biol. Chem. (2014)

A comparison between HbA (traces A) and LtHb (traces B) of the rate of nitrite reductase at pH 7.0 monitored as the decay of the 430 nm Sôret band as a function of the nitrite to heme ratio: 1:1 (a), 2:1 (b), and 5:1 (c). The heme concentration in all cases was ∼0.20 mm. The red lines represent fits to the data using Origin 8.5 as described under “Experimental Procedures.” The traces were all normalized to better expose the comparison of the kinetics.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4281771&req=5

Figure 1: A comparison between HbA (traces A) and LtHb (traces B) of the rate of nitrite reductase at pH 7.0 monitored as the decay of the 430 nm Sôret band as a function of the nitrite to heme ratio: 1:1 (a), 2:1 (b), and 5:1 (c). The heme concentration in all cases was ∼0.20 mm. The red lines represent fits to the data using Origin 8.5 as described under “Experimental Procedures.” The traces were all normalized to better expose the comparison of the kinetics.
Mentions: Fig. 1 shows a comparison between HbA and LtHb with respect to the normalized nitrite-induced decay of the deoxyheme population as a function of the ratio of added nitrite to heme while keeping the heme concentrations relatively fixed. It can be seen that at all ratios of nitrite to heme LtHb appears to exhibit two distinct phases, whereas under these conditions only one phase is observed for HbA. Exponential rates were calculated using both single and double exponential fitting algorithms associated with the program in Origin 8.5 (y = y0 + Ae−kt or y = y0 + A1e−kt1 + A2e−kt2). For HbA, a single exponential algorithm fit extremely well; however, for LtHb, the single exponential fit was poor, whereas the double exponential fit was much better. The goodness of fit for each of the kinetic curves was determined by comparing both the R2 value and the χ2 value for each equation used. Fits were chosen that had R2 values closest to 1 (0.97–0.99) or χ2 values of 10−4 or less.

Bottom Line: A potentially important additional property is the capacity of the HBOC either to generate nitric oxide (NO) or to preserve NO bioactivity to compensate for decreased levels of NO in the circulation.The results show that LtHb undergoes the same reactions as HbA and that the reduced efficacy for these reactions for LtHb relative to HbA is consistent with the much higher redox potential of LtHb.Evidence of functional heterogeneity in LtHb is explained in terms of the large difference in the redox potential of the isolated subunits.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461.

Show MeSH
Related in: MedlinePlus