Richards Mark P, Dettmann Mark A, Grunwald Eric W
Meat Science and Muscle Biology Laboratory, Department of Animal Sciences, University of Wisconsin--Madison, 1805 Linden Drive West, Madison, Wisconsin 53706, USA.
J Agric Food Chem. 2005 Dec 28;53(26):10231-8. doi: 10.1021/jf051923m.
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.
基于电喷雾电离质谱法，鳟鱼肌红蛋白的分子量为16017道尔顿。在鳟鱼血红蛋白中检测到了根效应（在pH 6.3时氧亲和力低），但在肌红蛋白中未检测到。在pH 6.3时，肌红蛋白的自氧化速度比阳极血红蛋白快（3.5倍）。在pH 6.3时，与肌红蛋白相比，阳极血红蛋白是清洗过的鳕鱼肌肉中脂质氧化的更好催化剂。这表明除高铁血红素蛋白形成之外的某些过程是脂质氧化过程中的限速步骤。使用从抹香鲸制备的脱辅基肌红蛋白突变体H64Y测定血红素损失率。阳极血红蛋白释放其血红素基团的速度比肌红蛋白快得多。在阳极血红蛋白和阴极血红蛋白的比较中，血红素损失率比自氧化率更能预测脂质氧化的开始。这些研究共同表明，血红素解离在不同血红素蛋白促进脂质氧化过程的能力中起主要作用。
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