Measurement of the strongly held water of myoglobin by drying

Abstract The karl Fischer reagent method has been used to study the drying of whale skeletal muscle myoglobin. Drying curves for metmyglobin were obtained by mechanical pumping (moderate vacuum) and diffusion pumping (high vacum) at 20, 10, 0, −10, and −20°C. Strongly held water is present in about the same amounts as were previously observed with lysozyme. Nearly all of this strongly held water is still present during the drying of acid denatured metmyoglobin. This suggest that a core structure containing strongly held water is still present at pH 4.0. Comparison of the drying of metmyoglobin, deoxymyoglobin, and oxymyoglobin indicates that the iron‐coordinated water of methyoglobin is the second most strongly held water of the molocule.