Localization of myoglobin in human muscle cells by immunoelectron microscopy

The localization of myoglobin in human skeletal muscle cell was studied by immunoelectron microscopy. The Fab'-horseradish peroxidase (HRP) conjugate was prepared by the maleimide method recently developed by Ishikawa et al. This method gave better recovery and less polymerization of HRP than the periodate method. By the direct immunoperoxidase method using this conjugate, myoglobin was shown to be localized in the I-band region of skeletal muscle cells. The outer membrane of mitochondria and triads stained intensely, but A-bands were not stained. Myonuclei and intermyofibrillar spaces were also not stained. The localization of myoglobin in the I-band implies its function in energy generation.