| Type: | Family | Name: | Biotinidase, eukaryotic |
| Description: | The major role of biotin has been as the coenzyme for four carboxylases in humans []. When biotin is lacking, specific enzymes called carboxylases cannot process proteins, fats, or carbohydrates. Biotin is attached to these carboxylase enzymes through an amino acid (the building material of proteins) called lysine, forming a complex called biocytin. For biotin recycling, biotinidase (encoded by the BTD gene) acts as a hydrolase by cleaving biocytin and biotinyl-peptides, this frees the biotin for reutilisation. Biotinidase is also important for making biotin bioavailable from bound dietary sources. Biotinidase is biotinylated in the presence of biocytin, but not biotin, at neutral and alkaline pH. It has biotinyl-transferase activities that result in the transfer of biotin from biocytin to nucleophilic acceptors, such as histones [].Biotinidase deficiency (also called late-onset multiple carboxylase deficiency) is an autosomal recessively inherited disorder that is characterised by the failure to recycle biotin and can result in neurological and cutaneous abnormalities, but can be treated effectively with biotin supplementation []. Mutations that cause biotinidase deficiency include missense mutations that alter functional amino acids which are likely conserved in species that depend on biotin recycling []. | Short Name: | Biotinidase_euk |
