On the Content of Myoglobin in Human Muscles

A quantitative method of determining the content of myoglobin and hemoglobin in human muscle is described. A piece of muscle, 1–4 g, is ground with dry ice, homogenized and extracted with 0.02 M phosphate buffer, pH 7.4. After being centrifuged at 15,000 × g, the solution is concentrated by dialysis against 25% polyethylene glycol solution. The hemoproteins are separated by gel filtration on Sephadex G 75, identified by the absorption spectra of their carbon monoxide compounds and quantitatively determined by the pyridine hemochrome method. The content of hemoprotein is calculated as per cent of dry weight, the latter being determined on the original homogenate. In an autopsy material, mainly consisting of patients in upper age‐groups with chronic disease and modest physical activity, average values of 0.9 g myoglobin per 100 g dry muscle were found in hearts (left ventricle), whereas corresponding values for diaphragm, abdominal muscle and muscles of the thigh were 1.1, 1.6 and 2.2 g per 100 g dry muscle. It is assumed that values in healthy adults may well be somewhat higher. From these values it is calculated that the total amount of myoglobin in an adult male is in the range of 120–150 g, corresponding to an iron pool of 0.37‐0.47 g or approximately 7/5 of the amount of hemoglobin iron. Comparisons with determinations arrived at by other methods are made, and some aspects of the physiology of myoglobin and other hematin compounds are discussed. The insoluble or “residual” hematin has been determined. It could be shown that the major part of this hematin can be accounted for by the mitochondrial hemoproteins, the remaining part in all probability deriving from hemoglobin.