Defective mitochondrial BTD does not hydrolyse BCTN

Stable Identifier
Reaction [transition]
Homo sapiens
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Human biotinidase (BTD, EC (Cole et al. 1994) catalyzes the hydrolysis of biocytin (BCTN, aka biotinyl-lysine), a product of biotin dependent carboxylase degradation, to biotin (Btn) and lysine. The process results in the regeneration of free Btn, an essential coenzyme for 5 carboxylases necessary for normal metabolism in humans. BTD is both secreted from various cells and localised in the mitochondria (Wolf & Jensen 2005). BTD deficiency, an autosomal recessive disorder, results in a secondary Btn deficiency that leads to juvenile onset multiple carboxylase deficiency (MIM:253260) (Wolf et al. 1983). More than 165 mutations in BTD have been reported (Procter et al. 2013, Pomponio et al. 1995, Pomponio et al. 1996, Wolf et al. 1997, Pomponio et al. 2000) and are catalogued in the BTD database ( ).

Literature References
PubMed ID Title Journal Year
7758201 Biotinylation of biotinidase following incubation with biocytin

Hymes, J, Fleischhauer, K, Wolf, B

Clin. Chim. Acta 1995
7550325 Mutational hotspot in the human biotinidase gene causes profound biotinidase deficiency

Pomponio, RJ, Reynolds, TR, Cole, H, Buck, GA, Wolf, B

Nat. Genet. 1995
9375914 Profound biotinidase deficiency in two asymptomatic adults

Wolf, B, Norrgard, K, Pomponio, RJ, Mock, DM, McVoy, JR, Fleischhauer, K, Shapiro, S, Blitzer, MG, Hymes, J

Am. J. Med. Genet. 1997
23550138 The Biotinidase Gene Variants Registry: A Paradigm Public Database

Procter, M, Wolf, B, Crockett, DK, Mao, R

G3 (Bethesda) 2013
10801053 Novel mutations cause biotinidase deficiency in Turkish children

Pomponio, RJ, Coskun, T, Demirkol, M, Tokatli, A, Ozalp, I, H√ľner, G, Baykal, T, Wolf, B

J. Inherit. Metab. Dis. 2000
16150625 Evolutionary conservation of biotinidase: implications for the enzyme's structure and subcellular localization

Wolf, B, Jensen, K

Mol. Genet. Metab. 2005
7509806 Human serum biotinidase. cDNA cloning, sequence, and characterization

Cole, H, Reynolds, TR, Lockyer, JM, Buck, GA, Denson, T, Spence, JE, Hymes, J, Wolf, B

J. Biol. Chem. 1994
6883721 Biotinidase deficiency: the enzymatic defect in late-onset multiple carboxylase deficiency

Wolf, B, Grier, RE, Allen, RJ, Goodman, SI, Kien, CL

Clin. Chim. Acta 1983
Catalyst Activity

biotinidase activity of BTD mutants [mitochondrial matrix]

Normal reaction
Functional status

Loss of function of BTD mutants [mitochondrial matrix]

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