The assay of exocrinous peptidases in clinical chemistry

The various peptidases secreted by such exocrine tissues as gastric mucosa, pancreas and prostate are usually determined by catalytic methods. Another approach utilizes immunoassay. Endopeptidases were formerly assayed with protein substrates such as hemoglobin and albumin. These techniques are increasingly replaced by more specific ones using artificial peptide derivatives as substrates, some of which allow an increase in absorbance or fluorescence to be continuously recorded. The presently available methods of assaying pepsin, pancreatic trypsin, trypsinogen and carboxypeptidase A, enterokinase and several peptidases of human sperm are reviewed.