A New Method for the Determination of Total Bile Acids in Serum Using 3-Oxo-5β-Steroid Δ⁴-Dehydrogenase

Abstract

A newly developed enzymatic method for the determination of total bile acids in serum using 3α-Hydroxysteroid dehydrogenase (3α-HSD) and 3-oxo-5β-steroid Δ⁴-dehydrogenase (Δ⁴-DH) is described. This method is based ona principle that nitrotetrazolium blue (NTB) is reduced to diformazan with Δ⁴-DH, catalyzing Δ⁴-dehydrogenation of 3-oxo-bile acids. The sensitivity of this method is twofold higher than that of the method using a system of diaphorase-NTB with NAD-dependent 3α-HSD. The proposed method shows a satisfactory recovery (100.1%), a good reproducibility (CV of 4.55% for 11μmole/l) and a good correlation (r=0.995, n=137) to the previous method.