Pro-oxidative Characteristics of Trout Hemoglobin and Myoglobin:  A Role for Released Heme in Oxidation of Lipids

Abstract

The molecular mass of trout myoglobin was 16017 Da based on electrospray ionization mass spectrometry. A Root effect (low oxygen affinity at pH 6.3) was determined in trout hemoglobin but not myoglobin. At pH 6.3, myoglobin autoxidized more rapidly (3.5-fold) as compared to anodic hemoglobin. Anodic hemoglobin was a better catalyst of lipid oxidation in washed cod muscle as compared to myoglobin at pH 6.3. This suggested that some process other than met heme protein formation was the rate-limiting step in lipid oxidation processes. Heme loss rates were determined using the apomyoglobin mutant H64Y prepared from sperm whale. Anodic hemoglobin released its heme group much more rapidly than myoglobin. In comparisons of anodic and cathodic hemoglobins, heme loss rate better predicted the onset of lipid oxidation than autoxidation rate. These studies collectively suggest that heme dissociation has a primary role in the ability of different heme proteins to promote lipid oxidation processes.

Effect of heating oxyhemoglobin and methemoglobin on microsomes oxidation

“…Mb and Hb have been reported to promote lipid oxidation in muscle based foods (Baron, Andersen 2002, Kanner, Harel 1985, Grunwald, Richards 2006a, Richards, Dettmann et al 2005. The ability of Mb and Hb to promote oxidation is attributed to their heme group so the oxidation mechanisms are common although subject to several conditions that may result in enhancement or decrease of their prooxidative activity (Carlsen, Moller et al 2005).…”

“…A faster autooxidation rate and low hematin affinity, which is increased in ferric heme forms, have been related with the increase of the lipid oxidation onset (Richards, Dettmann et al 2005, Grunwald, Richards 2006b, Richards, Nelson et al 2007). As for autoxidation, a series of reactions can be set (Carlsen, Moller et al 2005, Richards, Dettmann 2003, Gorelik, Kanner 2001, Yusa, Shikama 1987:…”

“…Various factors such as the ability of the Hb to autoxidize and release of hematin, the heme-iron moiety non-bound to the protein, have also been reported to be crucial in promoting lipid oxidation (Richards, Dettmann 2003, Grunwald, Richards 2006a, Richards, Dettmann et al 2005). …”

Use of “filtered smoke” and carbon monoxide with fish

“…For milkfish-Mb a MW of 15,900 Da is reported that is smaller than that of yellow fin tuna with 16,200 Da but larger than that for mackerel Mb and sardine Mb with 14,900 Da and 14,600 Da, respectively (Chen and Chow, 2001). The molecular weight of trout Mb was 16,017 Da based on electro spray ionisation mass spectrometry (Richards et al, 2005).…”

“…Results obtained since than mainly by US researchers can be derived from the abstract of presentations at IFT Annual Meetings 2004-2007, from research papers (Anderson and Wu, 2005;Balaban et al, 2005;Richards et al, 2005;Kristinsson et al, 2005Kristinsson et al, , 2007aKristinsson et al, and 2007bHuang et al, 2006;Smulevich et al, 2007) and from a recently published book . Mony and Kristinsson (2004) reported that thermal-denaturation experiments revealed that COHb was far by the most stable of the three types tested, followed by Oxy-Hb, with met-Hb being the least stable.…”