Quantitative assay to determine the hydrolytic activity of biotinidase

Abstract

A quantitative assay was standardized to determine the hydrolytic activity of biotinidase in human serum samples. The current Wolf et al. assay uses N-biotinyl-p-aminobenzoic acid as substrate. The assay's precision was improved by the addition of detergents to the sodium nitrite solution. This eliminated the formation of nitrogen bubbles during the diazotation reaction. Freezing and thawing of the serum samples did not affect the hydrolytic activity Farmaco's interference test showed positive results with sulfametoxasol/trimetoprima and procainel benzylpenicilline. The hydrolytic activity of biotinidase averaged 7.04 + 2.2 nmol/min/ml in a group of 205 healthy children. No statistically significant differences in enzymatic activity was observed between variables of sex, races and age group. The standardize assay can determine the hydrolytic activity of biotinidase human serum samples and can confirm the positive cases detected by neonatal screening programs for biotinidase deficiency.