title: Biotin dependent carboxylase activities in normal human and multicarboxylase deficient patient fibroblasts: relationship to the biotin content of the culture medium.
abstract: Three mitochondrial carboxylase activities can be depleted in skin fibroblasts from patients with the neonatal form of multiple carboxylase deficiency when the biotin content of the culture medium is lowered to 25 nmol/l. On the other hand this depletion can be achieved in control fibroblasts or in fibroblasts from patients with the late onset form of the deficiency when avidin (50 U/l) is added to the culture medium. The kinetics of the carboxylase activity decrease are nevertheless identical for control and for both types of fibroblasts. After depletion, control and late onset form fibroblasts recover their carboxylase activities at the same rate, whereas fibroblasts with the neonatal form of deficiency need longer times or higher concentrations of biotin to restore their carboxylase activities. These results are consistent with previous hypotheses concerning the origin of both forms of the deficiency. In addition, this technique provides a convenient access to human apocarboxylases, i.e. substrates for in vitro holocarboxylase synthetase investigation.
mesh_terms: D001710:Biotin / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000172:deficiency / Q000378:metabolism*; D003470:Culture Media; D004789:Enzyme Activation; D005347:Fibroblasts / Q000201:enzymology; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology
chemical_list: D003470:Culture Media; D001710:Biotin; D002262:Carboxy-Lyases