Publications

• Human serum biotinidase. cDNA cloning, sequence, and characterization.

  Cole H., Reynolds T.R., Lockyer J.M., Buck G.A., Denson T., Spence J.E., Hymes J., Wolf B.

  Biotinidase (EC 3.5.1.12) catalyzes the hydrolysis of biocytin, the product of biotin-dependent carboxylase degradation, to biotin and lysine. Biotinidase deficiency is an inherited metabolic disorder of biotin recycling that is characterized by neurological and cutaneous abnormalities, and can be ... >> More

  Biotinidase (EC 3.5.1.12) catalyzes the hydrolysis of biocytin, the product of biotin-dependent carboxylase degradation, to biotin and lysine. Biotinidase deficiency is an inherited metabolic disorder of biotin recycling that is characterized by neurological and cutaneous abnormalities, and can be successfully treated with biotin supplementation. Sequences of tryptic peptides of the purified human serum enzyme were used to design oligonucleotide primers for polymerase chain reaction amplification from human hepatic total RNA to generate putative biotinidase cDNA fragments. Sequence analysis of a cDNA isolated from a human liver library by plaque hybridization with the largest cDNA probe revealed an open reading frame of 1629 bases encoding a protein of 543 amino acid residues, including 41 amino acids of a potential signal peptide. Comparison of the open reading frame with the known biotinidase tryptic peptides and recognition of the expressed protein encoded by this cDNA by monoclonal antibodies prepared against purified biotinidase demonstrated the identity of this cDNA. Southern analyses suggested that biotinidase is a single copy gene and revealed that human cDNA probes hybridized to genomic DNA from mammals, but not from chicken or yeast. Northern analysis indicated the presence of biotinidase mRNA in human heart, brain, placenta, liver, lung, skeletal muscle, kidney, and pancreas. << Less

  J. Biol. Chem. 269:6566-6570(1994) [PubMed] [EuropePMC]

• Biotinidase and its roles in biotin metabolism.

  Hymes J., Wolf B.

  Biotinidase is the enzyme responsible for the recycling of the vitamin biotin. Biotinidase acts as a hydrolase by cleaving biocytin and biotinyl-peptides, thereby liberating biotin for reutilization. Biotinidase is also important for making biotin bioavailable from bound dietary sources. The inter ... >> More

  Biotinidase is the enzyme responsible for the recycling of the vitamin biotin. Biotinidase acts as a hydrolase by cleaving biocytin and biotinyl-peptides, thereby liberating biotin for reutilization. Biotinidase is also important for making biotin bioavailable from bound dietary sources. The interest in this enzyme has been increased by the discovery of biotinidase deficiency, an inherited biotin-responsive disorder that can result in neurological and cutaneous abnormalities, but can be treated effectively with biotin supplementation. Biotinidase has recently been shown to be biotinylated in the presence of biocytin, but not biotin, at neutral and alkaline pH. This raises the possibility that biotinidase acts as a biotin-binding or biotin-carrier protein. Biotinidase has also been shown to have biotinyl-transferase activity resulting in the transfer of biotin from biocytin to nucleophilic acceptors, such as histones. Transferase activity occurs at physiological pH and at physiological concentrations of biocytin and, therefore, may be the main function of the enzyme in serum and other tissues. These novel functions of the enzyme may indicate that biotinidase plays a critical role in the metabolism of biotin in nuclei, particularly of neuronal cells. The role of biotinidase in biotin metabolism may be a paradigm for better understanding the metabolism of other vitamins. << Less

  Clin Chim Acta 255:1-11(1996) [PubMed] [EuropePMC]

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