Strong ion reserve: a viewpoint on acid base equilibria and buffering.

Evidence suggests that strong ions can exist reversibly bound to proteins in a pH-dependent manner and that they can be recruited into the biological solution, modulating its strong ion difference in a process that opposes the acid base disturbances imposed on the system. These recruitable strong ions represent the solution's 'strong ion reserve'. The physiologic [corrected] role of these protein-bound strong ions [corrected] in the buffering of acid base disorders is discussed.