High-performance liquid chromatographic microassay for l-glutamate:glyoxylate aminotransferase activity in human liver. Application in primary hyperoxaluria type 1

A rapid and sensitive liquid chromatographic technique to determine L-glutamate: glyoxylate and aminotransferase (EC 2.6.1.4) activity in human liver is described. Homogenised tissue was incubated for 60 min in the presence of substrates and the 2-oxoglutarate generated was converted into the corresponding phenylhydrazone which was determined using reversed-phase high-performance liquid chromatography. The procedure allowed the detection of the enzyme activity expressed by 7.5 μg of liver protein, it was more sensitive and less time-consuming than the spectrophotometric procedure previously used. No significant differences were found between normal controls and patients with primary hyperoxaluria. In an 8-month-infant with primary hyperoxaluria type 1, the enzyme activity was reduced to 16% of the average control values.