Assays / Genetic Enzymes / Galactokinase

Principle Of Method: The enzyme measured catalyses the reaction

Galactose + ATP ® Galactose 1-phosphate + ADP

[¹⁴C]-galactose is used as a substrate and the [¹⁴C]-galactose 1-phosphate formed is bound to DEAE-cellulose paper. Unreacted [¹⁴C]-galactose is removed by washing the paper, and the final bound product is determined by liquid scintillation counting.

Uses And Limitations Of The Method: The method is used to diagnose galactokinase deficiency galactosaemia using a heparinised blood specimen. It is also applicable to other tissues including chorionic villi or amniotic cells for prenatal diagnosis, but the SAS Laboratory does not routinely offer the analysis for this purpose. When deficient galactokinase activity is found galactose 1-phosphate uridyl transferase is assayed as a check on specimen adequacy. Prenatal diagnosis of kinase deficiency is possible but is not offered by the SAS laboratory.

Specimen Requirements: Blood. 2 ml lithium heparin (orange capped tube) unseparated and unfrozen. Send at room temperature to arrive at the laboratory within 24h of venepuncture.

Please Always Contact The Laboratory Before Sending Blood For This Assay.

The Laboratory Recommends Use Of A Courier Service Or Royal Mail Special Delivery For Sending All Specimens To The Laboratory.

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