Biotinidase functions to recycle biotin in the body by cleaving biocytin (biotin-epsilon-lysine), a normal product of carboxylase degradation, resulting in regeneration of free biotin.

Biotinidase has also been shown to have biotinyl-transferase activity. Defects in the biotinidase gene cause multiple carboxylase deficiency. [provided by RefSeq, Jul 2008]