Ion-exchange reactions between cartilage and various cations

Abstract

Some of the factors which influence exchange reactions between cations and cartilage were investigated. A fraction of the cations initially bound to cartilage does not exchange readily with other cations. Those cations which do exchange readily do so reversibly. The affinities of some cations for cartilage were measured and recorded in the form of exchange constants, calculated from a Rothmund and Kornfeld (1918) equation. The order of increasing affinity for cartilage is K+, Na+, Mg2+, Ca2+, Sr2+, Ba2+, Be2+ (probably a complex ion) and Cu2+ (probably a complex ion). A comparison of this affinity series with those obtained in studies on sulphated mucopolysaccharides and on the mechanism of calcification was made.