Inability of cholylglycine hydrolase to cleave the amide bond of tauronorcholic acid.

High pressure liquid chromatography, glass capillary gas chromatography and liquid secondary ion mass spectrometry have been used to demonstrate that the amide bond of the taurine conjugate of norcholic acid, a homolog of cholic acid which contains one less methylene group in the side chain, cannot be hydrolyzed enzymatically by cholylglycine hydrolase. Conventional alkaline hydrolysis cleaved the amide bond of both taurocholate and tauronorcholate, producing the free acids. Treatment with cholylglycine hydrolase yielded the free acid for taurocholate but failed to affect tauronorcholate, which was recovered quantitatively.