A solid-state NMR study of protein mobility in lyophilized protein-sugar powders

Abstract

The molecular mobility of protein in lyophilized lysozyme-sugar systems stored at different relative humidities was studied using solid-state NMR. Relaxation measurements, T1 of high-frequency (MHz), and T1p, of low-frequency (kHz) motions, were performed on lysozyme lyophilized with lactose and trehalose. Molecular aggregation and enzymatic activity of the protein were determined using HPLC and bio-assays. An increase in hydration had little effect on the T1p values of pure lysozyme, trehalose, lactose, trehalose-lysozyme, and lysozyme at low lactose concentrations. The T1 values of pure sugar increased as moisture content increased. The presence of both sugars led to increased T1 values of..