Related Experiment Videos
A new continuous automated assay for the determination of intestinal lactase
1Laboratoire de Biochimie Appliquée (Faculté de Pharmacie), Université Louis-Pasteur de Strasbourg, Illkirch, France. isall@evc.net
Background:
A reliable, sensitive and practicable method for the measurement of intestinal lactase activity is needed.
Method:
The assay is based on the continuous measurement of released glucose by a coupled hexokinase/glucose-6-phosphate dehydrogenase (HK/G6PDH) reagent.
Results:
The procedure was first optimized for lactase from rat intestinal mucosa. The optimum pH is 6.5 and apparent Km was 17 mmol/l for lactose. The procedure was also adapted on a Cobas Mira automated analyzer; progress curves of the reaction rate can be continuously monitored. The automated assay correlated strongly with the conventional method of Dahlqvist (r(2) = 0.996). The described method has also been applied to human intestinal mucosa biopsies after determination of the catalytic properties of human enzyme (optimum pH 6.0 and apparent Km 34 mmol/l).
Conclusion:
The HK/G6PDH method is reliable, rapid, sensitive and easy to perform both manually as well as in the automated version. It is optimized for human and rat intestinal lactase.