Pyruvate carboxylase, activity

Yu, A., Drejer, J., Hertz, L. etal. Pyruvate carboxylase activity in primary cultures of astrocytes and neurons. /. Neurochem. 41 1484-1487,1983. 

Willmer, C.M. (1983). Phosphoeno/pyruvate carboxylase activity and stomatal operation. Physiologie Vegetale 21, 943-53. 

Bannister DW (1976a) The biochemistry of fatty liver and kidney syndrome. Biotin-mediated restoration of hepatic gluconeogenesis in vitro and its relationship to pyruvate carboxylase activity. Biochemical Journal 156, 167-73. 

A 3-month-old male infant developed seizures and progressively worsened, showing hypotonia, psychomotor retardation, and poor head control. He had lactic acidosis and an elevated plasma pyravate level, both more than seven times the normal amount. Pyruvate carboxylase activity was measured using extracts of fibroblasts and was found to be less than 1 percent of the normal level. Oral administration of which of the following amino acids would you recommend as the best therapy for this patient ... 

Although not strictly necessary, it is worthwhile to establish the lactate concentration in blood and urine, the organic acids in urine and the amino acids in serum, urine and CSR (for follow-up, therapy, tissue specificity). Determine pyruvate carboxylase activity. CT, computed tomography MRI, magnetic resonance imaging MRS, magnetic resonance spectroscopy... 

This assay is based on the formation of holopyruvate carboxylase from apopyru-vate carboxylase and biotin, followed by the determination of the pyruvate carboxylase activity. The activity is proportional to the amount of biotin available to form the active holoenzyme (63). This method is not very easy to use and involves unpurified yeast enzymes, but its sensitivity is good (as low as 0.5 ng). 

Brunette, M.G., Delvin, E., Hazel, B. and Scriver, C.R. (1972), Thiamin responsive lactic acidosis in a patient with deficient low Km pyruvate carboxylase activity in liver. Pediatrics, 50,702. 

Feldman, G.L. and Wolf, B. (1980), Measurement of pyruvate carboxylase activity in amniotic fluid cells. Pediatr. Res., 14,153. 

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