Improved hydrolysis of urinary 17-hydroxycorticosteroid glucuronides with beta-glucuronidase from Helix pomatia, on...

Sodium sulfate increases the hydrolysis of urinary 17-hydroxycorticosteroid glucuronides with beta-glucuronidase preparations derived from Helix pomatia because it removes the inhibitory activity of urinary high-molecular-weight substances. For maximum hydrolysis of urinary 17-hydroxycorticosteroid glucuronides, the hydrolysis [5 ml of urine, 0.5 ml of 2 mol/liter acetate buffer (pH 5.0)] should be conducted in the presence of sodium sulfate (final concentration: 80 g/liter) with (a) 600 Fishman units of the enzyme per milliliter of urine (18 h at 52 degrees C) or (b) with 1500 units of the enzyme per milliliter of urine (3 h at 57 degrees C). Under conditions a, analytical recovery of steroid glucuronides added to 12 urine samples was 99 +/- 2.1% (96-102%). Values obtained for 20 urine samples with this method were 99 +/- 2.7% (93-104%) as great as those yielded by a method in which 600 units of the enzyme from bovine liver are used together with sodium sulfate (18 h at 48 degrees C).