Interesting and useful biochemical properties of lanthanides

Lanthanide ions possess useful spectroscopic and other chemical properties which make them valuable probes of the interaction of Ca2+ with biological systems. These properties are outlined for 15 lanthanides. The interactions of lanthanides with several enzymes which either have an absolute dependence on Ca2+ or whose activity is stimulated by Ca2+ are described; interactions of other proteins which have been probed with lanthanides are also briefly outlined. The use of lanthanides as a probe for the role of Ca2+ in cellular metabolism are discussed. The unique properties of Ln3+ have also made them useful adjuncts to electron microscopy, microhistochemistry and to new separational techniques used in affinity chromatography and the magnetic separation of particles. Possible uses of lanthanides in medicine, e.g. nuclear medicine, are briefly indicated. (U.K.)