Terbium ions are used as fluorescent probes to characterize binding sites
in biological macromolecules (Vazquez-Ibar et al, 2002). Terbium has no known
essential biological function, but in the absence of Ca2+,
Tb3+ restored 76% of Bacillus
subtilis α-amylase activity (Smolka et al, 1971).
For more information:
Medline for terbium AND bacteria