Determination of beta-aspartylpeptidase activity in human faeces by high-performance liquid chromatography using pre-column derivatization with phenyl isothiocyanate
Van Der Leij, F.R.; Welling, G.W.
Journal of Chromatography 383(1): 35-42
1986
ISSN/ISBN: 0021-9673 PMID: 3818845 Document Number: 279635
Bacterial enzymes are responsible for degradation of .beta.-aspartyl peptides in the intestinal tract. These peptides, especially the dipeptide .beta.-aspartylglycine, are useful as indicators of an impaired anaerobic intestinal microflora of antibiotic-treated patients. A method to separate the dipeptides .beta.-aspartylalanine, .beta.-aspartylglutamine, .beta.-aspartylglycine and .beta.-aspartylserine, using reversed-phase high-performance liquid chromatography and pre-column derivatization with phenyl isothiocyanate, was developed. This method was used to determine .beta.-aspartylpeptidase activity in faecal supernatants of healthy human volunteers and antibiotic-treated patients with .beta.-aspartylglycine as substrate. This activity was absent in the antibiotic-treated group, while in individuals with an intact intestinal flora it ranged from 16 to 100% degradation per 18 h. In addition, it was found that faecal enzyme preparations cleaved .beta.-aspartylglycine at a much lower rate than the other .beta.-aspartyl peptides.