Dielectric relaxation in the kHz to MHz range displayed by hydrated powders of the protein lysozyme at room temperature is mainly due to protons migrating between ionized side chains. Quite recently we have measured the frequency and temperature dependence of this relaxation, and we have detected the freezing to a broad distribution of relaxation times, typical of proton glasses. Below the freezing temperature of about 270 K the system is not ergodic, in analogy with the behavior of proton glass crystals made up by random mixtures of ferro- and antiferroelectric compounds.